feat(FN-5115): complete Step 2 — add done pause backfills

Fusion-Task-Id: FN-5115
Fusion-Task-Lineage: 5c3d9d42-9dcd-4ebb-ba10-8a4b14d541dd

packages/core/src/db.ts

@@ -120,7 +120,7 @@ export function probeFts5(db: DatabaseSync): boolean {
 
 // ── Schema Definition ────────────────────────────────────────────────
 
-const SCHEMA_VERSION = 87;
+const SCHEMA_VERSION = 88;
 
 function normalizeTaskComments(
   steeringComments: SteeringComment[] | undefined,
@@ -3433,6 +3433,28 @@ export class Database {
       });
     }
 
+    if (version < 88) {
+      this.applyMigration(88, () => {
+        try {
+          const result = this.db
+            .prepare(`UPDATE tasks
+                SET paused = 0,
+                    userPaused = 0,
+                    pausedByAgentId = NULL,
+                    pausedReason = NULL
+              WHERE column = 'done'
+                AND (paused = 1
+                  OR userPaused = 1
+                  OR pausedByAgentId IS NOT NULL
+                  OR pausedReason IS NOT NULL)`)
+            .run();
+          console.log(`[done-paused-backfill] db.ts migration repaired ${result.changes} done task rows`);
+        } catch (error) {
+          console.warn("[done-paused-backfill] db.ts migration failed", error);
+        }
+      });
+    }
+
   }
 
   /**

packages/core/src/store.ts

@@ -882,6 +882,8 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
   private lastKnownModified: number = 0;
   /** ISO timestamp of last poll — used to filter changed tasks */
   private lastPollTime: string | null = null;
+  /** One-shot startup sweep flag for clearing stale pause fields on done tasks. */
+  private donePauseBackfillDone = false;
   /** Short-lived startup memo for repeated slim listTasks reads before steady-state watch/polling. */
   private startupSlimListMemo = new Map<string, { expiresAt: number; promise: Promise<Task[]> }>();
   private static readonly STARTUP_SLIM_LIST_MEMO_TTL_MS = 2_500;
@@ -6513,6 +6515,25 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       this.taskCache.set(task.id, { ...task });
     }
 
+    if (!this.donePauseBackfillDone) {
+      const repairedTaskIds: string[] = [];
+      for (const [taskId, cachedTask] of this.taskCache.entries()) {
+        if (cachedTask.column !== "done") continue;
+        if (!this.clearDoneTransientFields(cachedTask)) continue;
+
+        await this.atomicWriteTaskJson(this.taskDir(taskId), cachedTask);
+        this.taskCache.set(taskId, { ...cachedTask });
+        repairedTaskIds.push(taskId);
+      }
+      this.donePauseBackfillDone = true;
+
+      storeLog.info("done-task pause metadata backfill completed", {
+        phase: "watch:done-pause-backfill",
+        repairedCount: repairedTaskIds.length,
+        repairedTaskIds: repairedTaskIds.slice(0, 20),
+      });
+    }
+
     // Store current lastModified
     this.lastKnownModified = this.db.getLastModified();
     // Initialize lastPollTime so the first checkForChanges() cycle filters by