feat(FN-2471): persist source issue provenance in task storage

- Add TaskSourceIssue contract and thread sourceIssue through Task, TaskCreateInput, archived task entries, and TaskStore serialization paths.
- Extend SQLite schema to v45 with sourceIssue* columns and add migration coverage for v44 upgrades plus legacy JSON migration import.
- Persist, update, clear, and archive/unarchive sourceIssue metadata in TaskStore with dedicated regression tests.
- Update core and dashboard tests to schema v45 expectations and stabilize flaky modal assertions with async waits.

packages/core/src/db.ts

@@ -86,7 +86,7 @@ export function probeFts5(db: DatabaseSync): boolean {
 
 // ── Schema Definition ────────────────────────────────────────────────
 
-const SCHEMA_VERSION = 44;
+const SCHEMA_VERSION = 45;
 
 function normalizeTaskComments(
   steeringComments: SteeringComment[] | undefined,
@@ -199,6 +199,11 @@ CREATE TABLE IF NOT EXISTS tasks (
   workflowStepResults TEXT DEFAULT '[]',
   prInfo TEXT,
   issueInfo TEXT,
+  sourceIssueProvider TEXT,
+  sourceIssueRepository TEXT,
+  sourceIssueExternalIssueId TEXT,
+  sourceIssueNumber INTEGER,
+  sourceIssueUrl TEXT,
   mergeDetails TEXT,
   breakIntoSubtasks INTEGER DEFAULT 0,
   enabledWorkflowSteps TEXT DEFAULT '[]',
@@ -1735,6 +1740,19 @@ export class Database {
       });
     }
 
+    // Source issue provenance contract (FN-2471)
+    // Persists durable source identity for imported issues separately from
+    // transient/live issueInfo status snapshots.
+    if (version < 45) {
+      this.applyMigration(45, () => {
+        this.addColumnIfMissing("tasks", "sourceIssueProvider", "TEXT");
+        this.addColumnIfMissing("tasks", "sourceIssueRepository", "TEXT");
+        this.addColumnIfMissing("tasks", "sourceIssueExternalIssueId", "TEXT");
+        this.addColumnIfMissing("tasks", "sourceIssueNumber", "INTEGER");
+        this.addColumnIfMissing("tasks", "sourceIssueUrl", "TEXT");
+      });
+    }
+
   }
 
   /**