FN-6704: capture merge LOC for productivity analytics

Capture merge-time diff stats so Command Center Productivity can report real Lines changed when available.

- Add nullable additions/deletions columns to task commit associations with migration and storage normalization.
- Persist git shortstat counts from merge association paths without blocking merges when stats are unavailable.
- Aggregate Productivity LOC from recorded commit stats while preserving the unavailable sentinel for historical unknowns.
- Cover migration, store upsert, analytics, and merger association stats behavior with tests and documentation.

Files changed:
 .changeset/fn-6704-command-center-loc.md           |  5 ++
 docs/architecture.md                               |  4 +-
 docs/storage.md                                    |  3 +
 packages/core/src/__tests__/db-migrate.test.ts     | 32 ++++----
 packages/core/src/__tests__/db.test.ts             | 90 ++++++++++++++++------
 .../src/__tests__/productivity-analytics.test.ts   | 47 +++++++++--
 packages/core/src/__tests__/store-upsert.test.ts   | 40 ++++++++++
 packages/core/src/db.ts                            | 14 +++-
 packages/core/src/productivity-analytics.ts        | 56 +++++++++-----
 packages/core/src/store.ts                         | 17 +++-
 packages/core/src/task-lineage.ts                  |  2 +
 packages/core/src/types.ts                         |  2 +
 .../merger-commit-association-stats.test.ts        | 90 ++++++++++++++++++++++
 packages/engine/src/merger-ai.ts                   |  2 +
 packages/engine/src/merger.ts                      | 17 +++-
 15 files changed, 349 insertions(+), 72 deletions(-)

Fusion-Task-Id: FN-6704

Fusion-Task-Lineage: f079fecb-eade-4318-bc55-23aa48097b4a

.changeset/fn-6704-command-center-loc.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": minor
+---
+
+Populate Command Center Productivity Lines changed from merge-time commit association diff stats when available.

docs/architecture.md

@@ -855,7 +855,7 @@ Operator setup + troubleshooting guide: **[Remote Access runbook](./remote-acces
 Key server capabilities:
 - REST APIs for tasks, git, GitHub, agents, missions, planning, automations/routines, settings
 - System stats snapshot and vitest process controls APIs (`GET /api/system-stats`, `POST /api/kill-vitest`) exposing dashboard process/system telemetry (including app CPU percentage and host memory rendered as numeric values, radial gauges, and trend sparklines in the Command Center System area), task/agent aggregates, and manual vitest process termination
-- Command Center analytics APIs (`GET /api/command-center/tokens`, `/tools`, `/activity`, `/productivity`, `/team`, `/github`, `/signals`, `/live`) are project-scoped dashboard routes; `/signals` aggregates real local `incidents` rows for total/open/resolved counts, MTTR, and source/severity/status breakdowns and returns honest empty/unavailable sentinels instead of synthetic signal volume.
+- Command Center analytics APIs (`GET /api/command-center/tokens`, `/tools`, `/activity`, `/productivity`, `/team`, `/github`, `/signals`, `/live`) are project-scoped dashboard routes. `/productivity` reads Lines changed from nullable `task_commit_associations.additions`/`deletions` merge-time diff stats and keeps the unavailable sentinel when no in-range association has stats. `/signals` aggregates real local `incidents` rows for total/open/resolved counts, MTTR, and source/severity/status breakdowns and returns honest empty/unavailable sentinels instead of synthetic signal volume.
 - Remote access APIs (`/api/remote/*`) for provider config, activation, tunnel lifecycle, status, token issuance, authenticated URL generation, and QR payload generation
   - Operational runbook (prereqs/security/troubleshooting): [`docs/remote-access.md`](./remote-access.md)
   - `/api/remote/tunnel/start`, `/api/remote/tunnel/stop`, and `/api/remote/tunnel/kill-external` cover tunnel lifecycle and external funnel cleanup.
@@ -1458,6 +1458,8 @@ Dashboard session-diff route registration (`packages/dashboard/src/routes/regist
 - `legacy` = recovered via legacy task-id/subject matching
 - `ambiguous` = manual reconciliation where historical task-id attribution could be misleading
 
+Commit associations also carry optional `additions`/`deletions` shortstat counts captured by merge paths. These nullable fields are the Command Center Productivity LOC source: analytics sum additions + deletions only when at least one in-range row has stats, and preserve the `—` unavailable sentinel when all matching rows are `NULL` so unknown historical data is never rendered as `0`.
+
 ### Done-task files-changed sources of truth
 
 Done-task file-count surfaces intentionally distinguish three data sources:

docs/storage.md

@@ -391,9 +391,12 @@ The `tasks.githubTracking` JSON column stores per-task GitHub tracking state (`e
 The `tasks.sourceIssueClosedAt` column (migration 122) backs `TaskSourceIssue.closedAt`, a nullable ISO-8601 timestamp for the originating external issue's real close time. Going forward, the GitHub source-issue reconciler fills it when it closes the linked issue itself or observes GitHub's `closed_at`/`closedAt` value. Historical GitHub-imported `done`/`archived` rows that still have `NULL` can be filled retroactively by the optional manual `POST /api/git/github/backfill-source-issue-closed-at` sweep, now exposed as **Backfill exact close times** in the Command Center GitHub area's Fixed by Fusion card. The sweep is idempotent, paginated, writes only real GitHub `closed_at` values, reports `scanned`/`filled`/`skipped`/`errors`, and never overwrites an existing timestamp or runs automatically. Command Center "Fixed by Fusion" analytics read this exact timestamp when available and fall back to `updatedAt` only when it has not been observed.
 
 The `tasks.tokenUsage*` columns store cumulative per-task token usage for analytics. `tokenUsageModelProvider` and `tokenUsageModelId` are analytics-only snapshots of the actually-used runtime model recorded when usage is accumulated; they let Command Center group and price resolved-via-settings usage by provider/model without writing the task-level `modelProvider` / `modelId` own-model override fields that control future model resolution. Cost attribution reads the snapshot first and falls back to the legacy own-model columns for pre-snapshot rows.
+
+The `task_commit_associations.additions` and `task_commit_associations.deletions` columns (migration 123) store nullable merge-time git shortstat counts for the associated commit. Command Center Productivity uses `SUM(additions + deletions)` as the Lines changed source when at least one in-range association has non-null stats. `NULL` means stats were unknown or unavailable for that association, not zero; ranges with no non-null stats keep the unavailable `—` sentinel instead of reporting `0`.
 | `config` | Single-row project configuration (`nextId`, settings payload, workflow step counters). |
 | `workflow_steps` | Workflow step definitions (`prompt`/`script`) with phase, template metadata, and model overrides. |
 | `activityLog` | Per-project activity/event log with timestamp/type/task indexes. |
+| `task_commit_associations` | Commit-to-task-lineage associations for canonical and legacy landed-commit attribution. Includes nullable `additions`/`deletions` diff-stat columns captured at merge time for Command Center Productivity LOC; `NULL` means stats unknown, not zero. |
 | `archivedTasks` | Archived task snapshots (compact JSON payload + archive timestamp). |
 | `automations` | Scheduled automation definitions, run state, and run history. |
 | `agents` | Agent registry/state/task assignment metadata. |

packages/core/src/__tests__/db-migrate.test.ts

@@ -721,7 +721,7 @@ describe("schema migration", () => {
 
     const row = db.prepare("SELECT deletedAt FROM tasks WHERE id = 'FN-legacy'").get() as { deletedAt: string | null };
     expect(row.deletedAt).toBeNull();
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -783,7 +783,7 @@ describe("schema migration", () => {
       sourceIssueUrl: "https://github.com/runfusion/fusion/issues/10",
       sourceIssueClosedAt: null,
     });
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -816,7 +816,7 @@ describe("schema migration", () => {
       { id: "WS-001", mode: "prompt", gateMode: "advisory" },
       { id: "WS-002", mode: "script", gateMode: "advisory" },
     ]);
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -866,7 +866,7 @@ describe("schema migration", () => {
       reviewerContextRetryCount: 0,
       reviewerFallbackRetryCount: 0,
     });
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -895,7 +895,7 @@ describe("schema migration", () => {
 
     const columns = db.prepare("PRAGMA table_info(milestones)").all() as Array<{ name: string }>;
     expect(columns.map((column) => column.name)).toContain("acceptanceCriteria");
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -936,7 +936,7 @@ describe("schema migration", () => {
     const missionColumns = db.prepare("PRAGMA table_info(missions)").all() as Array<{ name: string }>;
     expect(missionColumns.map((column) => column.name)).toContain("autoMerge");
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
   });
 
@@ -970,7 +970,7 @@ describe("schema migration", () => {
       { id: "WS-002", mode: "script", enabled: 1, gateMode: "advisory" },
       { id: "WS-003", mode: "prompt", enabled: 0, gateMode: "advisory" },
     ]);
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -1007,7 +1007,7 @@ describe("schema migration", () => {
 
     const indexes = db.prepare("PRAGMA index_list(mission_goals)").all() as Array<{ name: string }>;
     expect(indexes.some((index) => index.name === "idxMissionGoalsGoalId")).toBe(true);
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -1068,7 +1068,7 @@ describe("schema migration", () => {
     expect(customFieldsColumn).toBeDefined();
     expect(customFieldsColumn?.dflt_value).toBe("'{}'");
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
   });
 
@@ -1106,7 +1106,7 @@ describe("schema migration", () => {
     const indexes = db.prepare("PRAGMA index_list(workflow_settings)").all() as Array<{ name: string }>;
     expect(indexes.some((index) => index.name === "idx_workflow_settings_project")).toBe(true);
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
   });
 
@@ -1188,7 +1188,7 @@ describe("schema migration", () => {
     expect(indexNames).toContain("idx_cli_sessions_chatSessionId");
     expect(indexNames).toContain("idx_cli_sessions_project_state");
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
   });
 
@@ -1220,7 +1220,7 @@ describe("schema migration", () => {
       .all() as Array<{ name: string }>;
     expect(columns.map((column) => column.name)).toContain("cliExecutorAdapterId");
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
   });
 
@@ -1230,7 +1230,7 @@ describe("schema migration", () => {
 
     const tables = db.prepare("SELECT name FROM sqlite_master WHERE type='table'").all() as Array<{ name: string }>;
     expect(tables.map((row) => row.name)).toContain("cli_sessions");
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
   });
 
@@ -1287,20 +1287,20 @@ describe("schema migration", () => {
       .get() as { migrated_fragment_id: string | null };
     expect(stepRow.migrated_fragment_id).toBeNull();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
   });
 
   it("migration 109 is idempotent on re-init", () => {
     const db = new Database(fusionDir);
     db.init();
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     db.close();
 
     // Re-open the same on-disk DB: already at 109, the 109 block must be a no-op.
     const reopened = new Database(fusionDir);
     reopened.init();
-    expect(reopened.getSchemaVersion()).toBe(122);
+    expect(reopened.getSchemaVersion()).toBe(123);
     const workflowColumns = reopened.prepare("PRAGMA table_info(workflows)").all() as Array<{ name: string }>;
     expect(workflowColumns.filter((c) => c.name === "kind")).toHaveLength(1);
     const stepColumns = reopened.prepare("PRAGMA table_info(workflow_steps)").all() as Array<{ name: string }>;

packages/core/src/__tests__/db.test.ts

@@ -334,7 +334,7 @@ describe("Database", () => {
     });
 
     it("seeds schema version", () => {
-      expect(db.getSchemaVersion()).toBe(122);
+      expect(db.getSchemaVersion()).toBe(123);
     });
 
     it("includes tokenUsageCacheWriteTokens on freshly initialized tasks table", () => {
@@ -393,7 +393,7 @@ describe("Database", () => {
 
     it("is idempotent - calling init() twice does not fail", () => {
       expect(() => db.init()).not.toThrow();
-      expect(db.getSchemaVersion()).toBe(122);
+      expect(db.getSchemaVersion()).toBe(123);
     });
     it("does not overwrite existing config on re-init", () => {
       // Update the config
@@ -1463,7 +1463,7 @@ describe("schema migrations", () => {
     db.init();
 
     // Verify version bumped to 29 (includes v1→v2 through v26→v29)
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     // Verify new columns exist and existing data is intact
     const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
@@ -1488,15 +1488,15 @@ describe("schema migrations", () => {
     const db = new Database(fusionDir);
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     // Re-init should not fail
     db.init();
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     // Re-init should not fail
     db.init();
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     db.close();
   });
@@ -1531,7 +1531,7 @@ describe("schema migrations", () => {
 
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
     expect(cols.map((col) => col.name)).toContain("priority");
@@ -1572,7 +1572,7 @@ describe("schema migrations", () => {
 
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
     const colNames = cols.map((col) => col.name);
@@ -1644,7 +1644,7 @@ describe("schema migrations", () => {
 
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
     const colNames = cols.map((col) => col.name);
@@ -1923,7 +1923,7 @@ describe("schema migrations", () => {
 
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     const cols = db.prepare("PRAGMA table_info(chat_messages)").all() as Array<{ name: string }>;
     expect(cols.map((col) => col.name)).toContain("attachments");
@@ -1997,7 +1997,7 @@ describe("schema migrations", () => {
 
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     const tables = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name = 'agentRatings'").all() as Array<{ name: string }>;
     expect(tables).toEqual([{ name: "agentRatings" }]);
@@ -2021,7 +2021,7 @@ describe("schema migrations", () => {
 
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     const tables = db.prepare("SELECT name FROM sqlite_master WHERE type='table' AND name = 'mission_events'").all() as Array<{ name: string }>;
     expect(tables).toEqual([{ name: "mission_events" }]);
@@ -2125,7 +2125,7 @@ describe("schema migrations", () => {
     db.init();
 
     // Verify version bumped to 29
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
 
     // Verify new columns exist and existing data is intact
     const cols = db.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
@@ -2308,6 +2308,48 @@ describe("schema migrations", () => {
     db.close();
   });
 
+  it("migration v123 adds nullable task commit association diff-stat columns", () => {
+    tmpDir = makeTmpDir();
+    const fusionDir = join(tmpDir, ".fusion");
+    const localDb = new Database(fusionDir);
+
+    localDb.exec(`
+      CREATE TABLE IF NOT EXISTS __meta (key TEXT PRIMARY KEY, value TEXT);
+      CREATE TABLE IF NOT EXISTS task_commit_associations (
+        id TEXT PRIMARY KEY,
+        taskLineageId TEXT NOT NULL,
+        taskIdSnapshot TEXT NOT NULL,
+        commitSha TEXT NOT NULL,
+        commitSubject TEXT NOT NULL,
+        authoredAt TEXT NOT NULL,
+        matchedBy TEXT NOT NULL,
+        confidence TEXT NOT NULL,
+        note TEXT,
+        createdAt TEXT NOT NULL,
+        updatedAt TEXT NOT NULL,
+        UNIQUE(taskLineageId, commitSha, matchedBy)
+      );
+    `);
+    localDb.exec("INSERT INTO __meta (key, value) VALUES ('schemaVersion', '122')");
+    localDb.exec("INSERT INTO __meta (key, value) VALUES ('lastModified', '1000')");
+    localDb.exec(`INSERT INTO task_commit_associations
+      (id, taskLineageId, taskIdSnapshot, commitSha, commitSubject, authoredAt, matchedBy, confidence, createdAt, updatedAt)
+      VALUES ('assoc-1', 'lin-1', 'FN-6704', 'abc123', 'subject', '2026-06-19T00:00:00.000Z', 'canonical-lineage-trailer', 'canonical', '2026-06-19T00:00:00.000Z', '2026-06-19T00:00:00.000Z')`);
+
+    localDb.init();
+
+    expect(localDb.getSchemaVersion()).toBe(123);
+    const columns = localDb.prepare("PRAGMA table_info(task_commit_associations)").all() as Array<{ name: string; notnull: number; dflt_value: string | null }>;
+    const additions = columns.find((column) => column.name === "additions");
+    const deletions = columns.find((column) => column.name === "deletions");
+    expect(additions).toMatchObject({ notnull: 0, dflt_value: null });
+    expect(deletions).toMatchObject({ notnull: 0, dflt_value: null });
+    const row = localDb.prepare("SELECT additions, deletions FROM task_commit_associations WHERE id = 'assoc-1'").get() as { additions: number | null; deletions: number | null };
+    expect(row).toEqual({ additions: null, deletions: null });
+
+    localDb.close();
+  });
+
   it("migration v74 adds tokenUsageCacheWriteTokens without data loss", () => {
     tmpDir = makeTmpDir();
     const fusionDir = join(tmpDir, ".fusion");
@@ -2344,7 +2386,7 @@ describe("schema migrations", () => {
 
     localDb.init();
 
-    expect(localDb.getSchemaVersion()).toBe(122);
+    expect(localDb.getSchemaVersion()).toBe(123);
     const columns = localDb.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
     expect(columns.map((column) => column.name)).toContain("tokenUsageCacheWriteTokens");
 
@@ -2655,7 +2697,7 @@ describe("createDatabase factory", () => {
     const db = createDatabase(fusionDir);
     db.init();
 
-    expect(db.getSchemaVersion()).toBe(122);
+    expect(db.getSchemaVersion()).toBe(123);
     expect(db.getLastModified()).toBeGreaterThan(0);
 
     db.close();
@@ -2809,7 +2851,7 @@ describe("migration v77 task token budget columns", () => {
 
       migrated = new Database(fusion);
       migrated.init();
-      expect(migrated.getSchemaVersion()).toBe(122);
+      expect(migrated.getSchemaVersion()).toBe(123);
       const rows = migrated.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>;
       const names = new Set(rows.map((row) => row.name));
       expect(names.has("tokenBudgetSoftAlertedAt")).toBe(true);
@@ -2840,7 +2882,7 @@ describe("migration v106 adds tasks.transitionPending (FN-1417)", () => {
     const fresh = new Database(fusion);
     try {
       fresh.init();
-      expect(fresh.getSchemaVersion()).toBe(122);
+      expect(fresh.getSchemaVersion()).toBe(123);
       const names = new Set(
         (fresh.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>).map((r) => r.name),
       );
@@ -2868,7 +2910,7 @@ describe("migration v106 adds tasks.transitionPending (FN-1417)", () => {
 
       migrated = new Database(fusion);
       migrated.init();
-      expect(migrated.getSchemaVersion()).toBe(122);
+      expect(migrated.getSchemaVersion()).toBe(123);
       const names = new Set(
         (migrated.prepare("PRAGMA table_info(tasks)").all() as Array<{ name: string }>).map((r) => r.name),
       );
@@ -2894,7 +2936,7 @@ describe("migration v107 adds workflow_run_branches + index (FN-1417)", () => {
     const fresh = new Database(fusion);
     try {
       fresh.init();
-      expect(fresh.getSchemaVersion()).toBe(122);
+      expect(fresh.getSchemaVersion()).toBe(123);
       const table = fresh
         .prepare("SELECT name FROM sqlite_master WHERE type='table' AND name = 'workflow_run_branches'")
         .get() as { name: string } | undefined;
@@ -2928,7 +2970,7 @@ describe("migration v107 adds workflow_run_branches + index (FN-1417)", () => {
 
       migrated = new Database(fusion);
       migrated.init();
-      expect(migrated.getSchemaVersion()).toBe(122);
+      expect(migrated.getSchemaVersion()).toBe(123);
       const table = migrated
         .prepare("SELECT name FROM sqlite_master WHERE type='table' AND name = 'workflow_run_branches'")
         .get() as { name: string } | undefined;
@@ -2954,7 +2996,7 @@ describe("migration v120 adds deployments + incidents tables (U13)", () => {
     const fresh = new Database(fusion);
     try {
       fresh.init();
-      expect(fresh.getSchemaVersion()).toBe(122);
+      expect(fresh.getSchemaVersion()).toBe(123);
       const tables = new Set(
         (
           fresh
@@ -3007,7 +3049,7 @@ describe("migration v120 adds deployments + incidents tables (U13)", () => {
       // creation while table + row assertions still pass. Assert the real index
       // names the v120 migration creates (idxDeployments*, idxIncidents*) so that
       // regression is caught.
-      expect(migrated.getSchemaVersion()).toBe(122);
+      expect(migrated.getSchemaVersion()).toBe(123);
       const tables = new Set(
         (
           migrated
@@ -3066,7 +3108,7 @@ describe("migration v67 drops orphan project auth tables", () => {
 
       migrated = new Database(fusion);
       migrated.init();
-      expect(migrated.getSchemaVersion()).toBe(122);
+      expect(migrated.getSchemaVersion()).toBe(123);
       const tables = migrated
         .prepare("SELECT name FROM sqlite_master WHERE type='table' AND name LIKE 'project_auth_%'")
         .all() as Array<{ name: string }>;
@@ -3093,7 +3135,7 @@ describe("migration v67 drops orphan project auth tables", () => {
 
     try {
       fresh.init();
-      expect(fresh.getSchemaVersion()).toBe(122);
+      expect(fresh.getSchemaVersion()).toBe(123);
       const tables = fresh
         .prepare("SELECT name FROM sqlite_master WHERE type='table' AND name LIKE 'project_auth_%'")
         .all() as Array<{ name: string }>;

packages/core/src/__tests__/productivity-analytics.test.ts

@@ -14,13 +14,19 @@ function insertTaskWithFiles(db: Database, id: string, files: string[], updatedA
   ).run(id, updatedAt, updatedAt, JSON.stringify(files));
 }
 
-function insertCommit(db: Database, id: string, sha: string, authoredAt: string): void {
+function insertCommit(
+  db: Database,
+  id: string,
+  sha: string,
+  authoredAt: string,
+  stats: { additions?: number | null; deletions?: number | null } = {},
+): void {
   db.prepare(
     `INSERT INTO task_commit_associations
        (id, taskLineageId, taskIdSnapshot, commitSha, commitSubject, authoredAt,
-        matchedBy, confidence, createdAt, updatedAt)
+        matchedBy, confidence, additions, deletions, createdAt, updatedAt)
-     VALUES (?, 'lin-1', 't-1', ?, 'subj', ?, 'canonical-lineage-trailer', 'canonical', ?, ?)`,
+     VALUES (?, 'lin-1', 't-1', ?, 'subj', ?, 'canonical-lineage-trailer', 'canonical', ?, ?, ?, ?)`,
-  ).run(id, sha, authoredAt, authoredAt, authoredAt);
+  ).run(id, sha, authoredAt, stats.additions ?? null, stats.deletions ?? null, authoredAt, authoredAt);
 }
 
 function insertPr(db: Database, id: string, createdAtMs: number): void {
@@ -74,13 +80,44 @@ describe("productivity-analytics", () => {
     expect(result.pullRequests).toBe(2);
   });
 
-  it("reports LOC as unavailable (null + unavailable:true), never 0", () => {
+  it("reports LOC as unavailable (null + unavailable:true), never 0 when no stats exist", () => {
     insertTaskWithFiles(db, "t1", ["src/a.ts"], "2026-03-01T00:00:00.000Z");
+    insertCommit(db, "c-null", "sha-null", "2026-03-01T00:00:00.000Z");
     const result = aggregateProductivityAnalytics(db, {});
     expect(result.loc).toEqual({ value: null, unavailable: true });
     expect(result.loc.value).not.toBe(0);
   });
 
+  it("sums additions and deletions into LOC when commit stats exist", () => {
+    insertCommit(db, "c1", "sha1", "2026-03-01T00:00:00.000Z", { additions: 10, deletions: 5 });
+    insertCommit(db, "c2", "sha2", "2026-03-02T00:00:00.000Z", { additions: 3, deletions: 2 });
+    insertCommit(db, "c-old", "sha-old", "2025-01-01T00:00:00.000Z", { additions: 100, deletions: 100 });
+
+    const result = aggregateProductivityAnalytics(db, { from: "2026-03-01T00:00:00.000Z", to: "2026-03-31T00:00:00.000Z" });
+    expect(result.commits).toBe(2);
+    expect(result.loc).toEqual({ value: 20, unavailable: false });
+  });
+
+  it("keeps the LOC sentinel when in-range commit rows have only null stats", () => {
+    insertCommit(db, "c1", "sha1", "2026-03-01T00:00:00.000Z");
+    insertCommit(db, "c2", "sha2", "2026-03-02T00:00:00.000Z", { additions: null, deletions: null });
+
+    const result = aggregateProductivityAnalytics(db, { from: "2026-03-01T00:00:00.000Z", to: "2026-03-31T00:00:00.000Z" });
+    expect(result.commits).toBe(2);
+    expect(result.loc).toEqual({ value: null, unavailable: true });
+    expect(result.loc.value).not.toBe(0);
+  });
+
+  it("sums only valued LOC rows while allowing partial commit-stat coverage", () => {
+    insertCommit(db, "c-null", "sha-null", "2026-03-01T00:00:00.000Z");
+    insertCommit(db, "c-additions", "sha-additions", "2026-03-02T00:00:00.000Z", { additions: 7 });
+    insertCommit(db, "c-deletions", "sha-deletions", "2026-03-03T00:00:00.000Z", { deletions: 4 });
+
+    const result = aggregateProductivityAnalytics(db, { from: "2026-03-01T00:00:00.000Z", to: "2026-03-31T00:00:00.000Z" });
+    expect(result.commits).toBe(3);
+    expect(result.loc).toEqual({ value: 11, unavailable: false });
+  });
+
   it("empty range returns zeroed structures, not nulls", () => {
     insertTaskWithFiles(db, "t1", ["src/a.ts"], "2026-03-01T00:00:00.000Z");
     insertCommit(db, "c1", "sha1", "2026-03-01T00:00:00.000Z");

packages/core/src/__tests__/store-upsert.test.ts

@@ -35,6 +35,46 @@ describe("TaskStore", () => {
   const insertLogEntryWithTimestamp = (...args: any[]) => (harness as any).insertLogEntryWithTimestamp(...args);
   const taskDir = (taskId: string) => join(rootDir, ".fusion", "tasks", taskId);
 
+  describe("task commit association diff stats", () => {
+    it("round-trips nullable additions and deletions without coercing unknown stats to zero", async () => {
+      const withStats = await store.upsertTaskCommitAssociation({
+        taskLineageId: "lineage-loc-stats",
+        taskIdSnapshot: "FN-6704",
+        commitSha: "abc123",
+        commitSubject: "feat: capture stats",
+        authoredAt: "2026-06-19T00:00:00.000Z",
+        matchedBy: "canonical-lineage-trailer",
+        confidence: "canonical",
+        additions: 12,
+        deletions: 3,
+      });
+      expect(withStats.additions).toBe(12);
+      expect(withStats.deletions).toBe(3);
+
+      await store.upsertTaskCommitAssociation({
+        taskLineageId: "lineage-loc-stats",
+        taskIdSnapshot: "FN-6704",
+        commitSha: "def456",
+        commitSubject: "fix: unknown stats",
+        authoredAt: "2026-06-19T01:00:00.000Z",
+        matchedBy: "canonical-lineage-trailer",
+        confidence: "canonical",
+      });
+
+      const associations = await store.getTaskCommitAssociationsByLineageId("lineage-loc-stats");
+      const persistedWithStats = associations.find((association) => association.commitSha === "abc123");
+      const persistedUnknownStats = associations.find((association) => association.commitSha === "def456");
+      expect(persistedWithStats).toMatchObject({ additions: 12, deletions: 3 });
+      expect(persistedUnknownStats?.additions).toBeUndefined();
+      expect(persistedUnknownStats?.deletions).toBeUndefined();
+
+      const rawUnknown = (store as any).db.prepare(
+        `SELECT additions, deletions FROM task_commit_associations WHERE commitSha = ?`,
+      ).get("def456") as { additions: number | null; deletions: number | null };
+      expect(rawUnknown).toEqual({ additions: null, deletions: null });
+    });
+  });
+
   describe("upsertTask regression coverage", () => {
     it("creates tasks successfully on a fresh database schema", async () => {
       const freshRoot = makeTmpDir();

packages/core/src/db.ts

@@ -162,7 +162,7 @@ export function isFts5CorruptionError(error: unknown): boolean {
 
 // ── Schema Definition ────────────────────────────────────────────────
 
-const SCHEMA_VERSION = 122;
+const SCHEMA_VERSION = 123;
 
 const TASKS_FTS_AUTOMERGE = 8;
 const TASKS_FTS_CRISISMERGE = 16;
@@ -476,6 +476,8 @@ CREATE TABLE IF NOT EXISTS task_commit_associations (
   matchedBy TEXT NOT NULL CHECK (matchedBy IN ('canonical-lineage-trailer', 'legacy-task-id-trailer', 'legacy-subject', 'manual-reconciliation')),
   confidence TEXT NOT NULL CHECK (confidence IN ('canonical', 'legacy', 'ambiguous')),
   note TEXT,
+  additions INTEGER,
+  deletions INTEGER,
   createdAt TEXT NOT NULL,
   updatedAt TEXT NOT NULL,
   UNIQUE(taskLineageId, commitSha, matchedBy)
@@ -4965,6 +4967,16 @@ export class Database {
       });
     }
 
+    // Migration 123: nullable merge-time diff stats for Command Center LOC analytics.
+    // FNXC:CommandCenterProductivity 2026-06-19-00:00:
+    // Productivity LOC must distinguish unknown historical commit stats from real zero-line commits. Store merge-time additions/deletions as nullable columns with no default; null means stats were unavailable, not zero.
+    if (version < 123) {
+      this.applyMigration(123, () => {
+        this.addColumnIfMissing("task_commit_associations", "additions", "INTEGER");
+        this.addColumnIfMissing("task_commit_associations", "deletions", "INTEGER");
+      });
+    }
+
   }
 
   /**

packages/core/src/productivity-analytics.ts

@@ -3,14 +3,15 @@ import type { Database } from "./db.js";
 /**
  * Productivity analytics: files modified (count + language distribution) from
  * `tasks.modifiedFiles`, commit associations from `task_commit_associations`,
- * pull requests from `pull_requests`, and LOC from commit diff stats.
+ * pull requests from `pull_requests`, and LOC from merge-time commit diff stats.
  *
- * **LOC availability.** Fusion does not currently persist commit diff line
+ * **LOC availability.** Fusion persists nullable `additions`/`deletions` on
- * stats (the `task_commit_associations` schema has no additions/deletions
+ * `task_commit_associations` when merge paths can capture git shortstat output.
- * columns). LOC is therefore reported as the documented unavailable sentinel —
+ * LOC is reported as a real value only when at least one in-range association
- * `{ value: null, unavailable: true }` — **never `0`**, so a missing data source
+ * has non-null stats. If the range has no recorded stats, the documented
- * is never mistaken for "zero lines changed". When a diff-stats source is added,
+ * unavailable sentinel — `{ value: null, unavailable: true }` — is preserved,
- * fill {@link LocSummary.value} and clear `unavailable`.
+ * **never `0`**, so missing historical data is not mistaken for "zero lines
+ * changed".
  *
  * Inclusivity: `from`/`to` bounds are inclusive. Tasks are filtered by
  * `updatedAt` (the last time the task — and therefore its modifiedFiles — was
@@ -32,8 +33,8 @@ export interface LanguageCount {
 }
 
 /**
- * LOC summary. `value` is null and `unavailable` true until a commit diff-stats
+ * LOC summary. `value` is null and `unavailable` true when no in-range commit
- * source exists — never `0`.
+ * association has diff stats — never `0` for unknown data.
  */
 export interface LocSummary {
   value: number | null;
@@ -51,7 +52,7 @@ export interface ProductivityAnalytics {
   commits: number;
   /** Rows in `pull_requests` in range. */
   pullRequests: number;
-  /** LOC from commit diff stats — unavailable until a source exists. */
+  /** LOC from commit association diff stats when at least one in-range row has stats. */
   loc: LocSummary;
 }
 
@@ -59,6 +60,13 @@ interface CountRow {
   count: number;
 }
 
+interface CommitStatsRow {
+  count: number;
+  additions: number | null;
+  deletions: number | null;
+  statsRows: number;
+}
+
 interface ModifiedFilesRow {
   modifiedFiles: string | null;
 }
@@ -73,8 +81,8 @@ function languageOf(path: string): string {
 
 /**
  * Aggregate productivity metrics over a date range. Empty range yields zeroed
- * structures (not nulls); LOC is always the unavailable sentinel until a
+ * structures (not nulls); LOC remains the unavailable sentinel unless at least
- * diff-stats source is wired.
+ * one in-range commit association carries diff stats.
  */
 export function aggregateProductivityAnalytics(
   db: Database,
@@ -135,13 +143,20 @@ export function aggregateProductivityAnalytics(
   }
   const commitWhere =
     commitClauses.length > 0 ? `WHERE ${commitClauses.join(" AND ")}` : "";
-  const commits = (
+  const commitStats = db
-    db
+    .prepare(
-      .prepare(
+      `SELECT
-        `SELECT COUNT(*) AS count FROM task_commit_associations ${commitWhere}`,
+         COUNT(*) AS count,
-      )
+         SUM(additions) AS additions,
-      .get(...commitParams) as CountRow
+         SUM(deletions) AS deletions,
-  ).count;
+         COUNT(CASE WHEN additions IS NOT NULL OR deletions IS NOT NULL THEN 1 END) AS statsRows
+       FROM task_commit_associations ${commitWhere}`,
+    )
+    .get(...commitParams) as CommitStatsRow;
+  const commits = commitStats.count;
+  const loc: LocSummary = commitStats.statsRows > 0
+    ? { value: (commitStats.additions ?? 0) + (commitStats.deletions ?? 0), unavailable: false }
+    : { value: null, unavailable: true };
 
   // Pull requests. `pull_requests.createdAt` is an INTEGER epoch-ms column, so
   // convert the ISO bounds to epoch ms for comparison.
@@ -169,7 +184,6 @@ export function aggregateProductivityAnalytics(
     byLanguage,
     commits,
     pullRequests,
-    // No commit diff-stats source yet — unavailable, never 0.
+    loc,
-    loc: { value: null, unavailable: true },
   };
 }

packages/core/src/store.ts

@@ -560,6 +560,8 @@ interface TaskCommitAssociationRow {
   matchedBy: TaskCommitAssociationMatchSource;
   confidence: TaskCommitAssociationConfidence;
   note: string | null;
+  additions: number | null;
+  deletions: number | null;
   createdAt: string;
   updatedAt: string;
 }
@@ -16202,14 +16204,16 @@ ${notificationsSection}`;
     });
     this.db.prepare(
       `INSERT INTO task_commit_associations
-       (id, taskLineageId, taskIdSnapshot, commitSha, commitSubject, authoredAt, matchedBy, confidence, note, createdAt, updatedAt)
+       (id, taskLineageId, taskIdSnapshot, commitSha, commitSubject, authoredAt, matchedBy, confidence, note, additions, deletions, createdAt, updatedAt)
-       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
        ON CONFLICT(taskLineageId, commitSha, matchedBy) DO UPDATE SET
          taskIdSnapshot = excluded.taskIdSnapshot,
          commitSubject = excluded.commitSubject,
          authoredAt = excluded.authoredAt,
          confidence = excluded.confidence,
          note = excluded.note,
+         additions = excluded.additions,
+         deletions = excluded.deletions,
          updatedAt = excluded.updatedAt`,
     ).run(
       association.id,
@@ -16221,6 +16225,8 @@ ${notificationsSection}`;
       association.matchedBy,
       association.confidence,
       association.note ?? null,
+      association.additions ?? null,
+      association.deletions ?? null,
       association.createdAt,
       association.updatedAt,
     );
@@ -16231,7 +16237,12 @@ ${notificationsSection}`;
     const rows = this.db.prepare(
       `SELECT * FROM task_commit_associations WHERE taskLineageId = ? ORDER BY authoredAt DESC, createdAt DESC`,
     ).all(lineageId) as TaskCommitAssociationRow[];
-    return rows.map((row) => normalizeTaskCommitAssociation({ ...row, note: row.note ?? undefined }));
+    return rows.map((row) => normalizeTaskCommitAssociation({
+      ...row,
+      note: row.note ?? undefined,
+      additions: row.additions ?? undefined,
+      deletions: row.deletions ?? undefined,
+    }));
   }
 
   async replaceLegacyTaskCommitAssociations(

packages/core/src/task-lineage.ts

@@ -42,6 +42,8 @@ export function normalizeTaskCommitAssociation(
   return {
     ...row,
     note: row.note?.trim() || undefined,
+    additions: row.additions ?? undefined,
+    deletions: row.deletions ?? undefined,
     confidence: row.confidence ?? classifyTaskCommitAssociationConfidence(row.matchedBy),
   };
 }

packages/core/src/types.ts

@@ -4387,6 +4387,8 @@ export interface TaskCommitAssociation {
   matchedBy: TaskCommitAssociationMatchSource;
   confidence: TaskCommitAssociationConfidence;
   note?: string;
+  additions?: number;
+  deletions?: number;
   createdAt: string;
   updatedAt: string;
 }

packages/engine/src/__tests__/merger-commit-association-stats.test.ts

@@ -0,0 +1,90 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { execSync, spawnSync } from "node:child_process";
+import { chmodSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import type { TaskStore } from "@fusion/core";
+import { recordCommitAssociationFromHead } from "../merger.js";
+
+const hasGit = spawnSync("git", ["--version"], { stdio: "pipe" }).status === 0;
+const describeIfGit = hasGit ? describe : describe.skip;
+
+function git(repo: string, command: string): string {
+  return execSync(command, { cwd: repo, encoding: "utf-8", stdio: ["pipe", "pipe", "pipe"] }).trim();
+}
+
+function makeRepo(): string {
+  const repo = mkdtempSync(join(tmpdir(), "fusion-merger-commit-assoc-"));
+  git(repo, "git init -b main");
+  git(repo, "git config user.email fusion@example.com");
+  git(repo, "git config user.name Fusion");
+  writeFileSync(join(repo, "file.txt"), "one\ntwo\n");
+  git(repo, "git add file.txt");
+  git(repo, "git commit -m 'initial commit'");
+  writeFileSync(join(repo, "file.txt"), "one\ntwo\nthree\nfour\n");
+  git(repo, "git add file.txt");
+  git(repo, "git commit -m 'update file'");
+  return repo;
+}
+
+function makeStore(): Pick<TaskStore, "upsertTaskCommitAssociation"> {
+  return {
+    upsertTaskCommitAssociation: vi.fn(async (association) => ({
+      id: "assoc-1",
+      createdAt: new Date().toISOString(),
+      updatedAt: new Date().toISOString(),
+      ...association,
+    })),
+  } as Pick<TaskStore, "upsertTaskCommitAssociation">;
+}
+
+describeIfGit("recordCommitAssociationFromHead", () => {
+  const cleanup: string[] = [];
+  let originalPath: string | undefined;
+
+  afterEach(() => {
+    if (originalPath !== undefined) process.env.PATH = originalPath;
+    while (cleanup.length > 0) {
+      rmSync(cleanup.pop()!, { recursive: true, force: true });
+    }
+  });
+
+  it("persists HEAD diff stats as additions and deletions", async () => {
+    const repo = makeRepo();
+    cleanup.push(repo);
+    const store = makeStore();
+
+    await recordCommitAssociationFromHead(store as TaskStore, repo, "FN-6704", "lineage-1");
+
+    expect(store.upsertTaskCommitAssociation).toHaveBeenCalledWith(expect.objectContaining({
+      taskLineageId: "lineage-1",
+      taskIdSnapshot: "FN-6704",
+      commitSubject: "update file",
+      additions: 2,
+      deletions: 0,
+    }));
+  });
+
+  it("persists the association without stats when shortstat capture fails", async () => {
+    const repo = makeRepo();
+    const fakeBin = mkdtempSync(join(tmpdir(), "fusion-fake-git-"));
+    cleanup.push(repo, fakeBin);
+    const realGit = execSync("command -v git", { encoding: "utf-8" }).trim();
+    const fakeGit = join(fakeBin, "git");
+    writeFileSync(fakeGit, `#!/bin/sh\nif [ "$1" = "show" ] && [ "$2" = "--shortstat" ]; then\n  echo shortstat failed >&2\n  exit 42\nfi\nexec ${realGit} "$@"\n`);
+    chmodSync(fakeGit, 0o755);
+    originalPath = process.env.PATH;
+    process.env.PATH = `${fakeBin}:${originalPath ?? ""}`;
+    const store = makeStore();
+
+    await recordCommitAssociationFromHead(store as TaskStore, repo, "FN-6704", "lineage-1");
+
+    expect(store.upsertTaskCommitAssociation).toHaveBeenCalledWith(expect.objectContaining({
+      taskLineageId: "lineage-1",
+      taskIdSnapshot: "FN-6704",
+      commitSubject: "update file",
+      additions: undefined,
+      deletions: undefined,
+    }));
+  });
+});

packages/engine/src/merger-ai.ts

@@ -1327,6 +1327,8 @@ async function finalizeMerged(
         authoredAt: mergedAt,
         matchedBy: "canonical-lineage-trailer",
         confidence: "canonical",
+        additions: insertions,
+        deletions,
       }).catch(() => undefined);
     }
   }

packages/engine/src/merger.ts

@@ -3833,7 +3833,7 @@ async function generateAiMergeSubject(
  * is a denormalized convenience for lineage lookups, not a correctness
  * invariant, so a missed write must not block the merge.
  */
-async function recordCommitAssociationFromHead(
+export async function recordCommitAssociationFromHead(
   store: TaskStore,
   rootDir: string,
   taskId: string,
@@ -3857,6 +3857,17 @@ async function recordCommitAssociationFromHead(
     );
     return;
   }
+  let additions: number | undefined;
+  let deletions: number | undefined;
+  try {
+    const shortstat = (await execAsync("git show --shortstat --format= HEAD", { cwd: rootDir })).stdout;
+    const parsed = parseShortstatSummary(shortstat);
+    additions = parsed.insertions;
+    deletions = parsed.deletions;
+  } catch (err: unknown) {
+    const message = err instanceof Error ? err.message : String(err);
+    mergerLog.warn(`${taskId}: commit-association diff stats unavailable; persisting lineage without LOC stats (${message})`);
+  }
   await store.upsertTaskCommitAssociation({
     taskLineageId: lineageId,
     taskIdSnapshot: taskId,
@@ -3865,6 +3876,8 @@ async function recordCommitAssociationFromHead(
     authoredAt,
     matchedBy: "canonical-lineage-trailer",
     confidence: "canonical",
+    additions,
+    deletions,
   });
 }
 
@@ -10385,6 +10398,8 @@ export async function aiMergeTask(
           authoredAt: mergeDetails.mergedAt ?? new Date().toISOString(),
           matchedBy: "canonical-lineage-trailer",
           confidence: "canonical",
+          additions: mergeDetails.insertions,
+          deletions: mergeDetails.deletions,
         });
       }
     }