B2 Phase 1 follow-up: plug lease orphan gap in advanceTaskStatus + scope interruptStaleRuns cleanup

Linus review T1 surfaced three real bugs in the B2 Phase 1 shadow
dual-write surface. Fix them in one pass.

1. advanceTaskStatus left task_leases behind on terminal (done /
   cancelled / blocked) and "return to queue" (todo / backlog)
   transitions. The status->phase trigger advanced tasks.phase but the
   lease row lingered as an orphan. dev-mode verifyPhaseConsistency
   could see the divergence; production silently drifted. Wrap the
   status UPDATE and an explicit DELETE FROM task_leases in a single
   transaction so no caller observes the intermediate state.

2. The no-restricted-syntax guard in eslint.config.mjs only matched
   literals shaped "UPDATE tasks SET status" -- advanceTaskStatus's
   dynamic `UPDATE tasks SET ${timestampSets.join(", ")}` slipped past,
   and so did saveTask / recoverStaleLocks (status not first column).
   Tighten the selectors to (a) match any status-write within UPDATE
   tasks regardless of column order, and (b) flag template literals
   whose head ends with `SET ` so dynamic helpers must carry an
   explicit eslint-disable with rationale. Five grandfathered sites
   now carry matching disables.

3. interruptStaleRuns scoped its task+lease cleanup with
   `WHERE finished_at = ?` against the freshly stamped timestamp --
   safe in isolation, vulnerable to ISO-millisecond ties with other
   already-interrupted runs. Capture the stale run ids before
   mutating anything and drive every downstream statement from that
   explicit id list. Original semantics preserved; scoping is exact.

Unit tests added in tests/unit/tasks-phase.test.ts cover the
advanceTaskStatus lease cleanup across done / cancelled / blocked /
todo, and pin the in_review case as "lease stays".

tests/unit/tasks-phase.test.ts

@@ -280,6 +280,116 @@ describe("tasks-phase helpers", () => {
     });
   });
 
+  describe("advanceTaskStatus lease cleanup", () => {
+    // B2 Phase 1 follow-up (Linus review ask #1): advanceTaskStatus
+    // used to write only the status column, leaving any lease row
+    // behind as an orphan. The helpers below seed a lease directly,
+    // then drive status transitions and assert the shadow row lifecycle.
+    function seedLease(taskId: string, runId: string): void {
+      const acquired = new Date().toISOString();
+      const expires = new Date(Date.now() + 60_000).toISOString();
+      (db as unknown as {
+        db: { prepare: (sql: string) => { run: (...args: unknown[]) => unknown } };
+      }).db
+        .prepare(
+          `INSERT OR REPLACE INTO task_leases
+             (task_id, run_id, acquired_at, expires_at, checkout_run_id)
+           VALUES (?, ?, ?, ?, ?)`,
+        )
+        .run(taskId, runId, acquired, expires, runId);
+    }
+
+    function readLease(taskId: string): { run_id: string } | undefined {
+      return (db as unknown as {
+        db: { prepare: (sql: string) => { get: (...args: unknown[]) => unknown } };
+      }).db
+        .prepare("SELECT run_id FROM task_leases WHERE task_id = ?")
+        .get(taskId) as { run_id: string } | undefined;
+    }
+
+    it("drops the lease when the task transitions to done", () => {
+      const companyId = createTestCompany(db);
+      createTestConnector(db);
+      const workspaceId = createTestWorkspace(db, companyId);
+      const agentId = createTestAgent(db, companyId, workspaceId);
+      const taskId = createTestTask(db, companyId, agentId, workspaceId);
+      const runId = createTestRun(db, companyId, taskId, agentId, workspaceId);
+
+      db.tasks.advanceTaskStatus(taskId, "in_progress");
+      seedLease(taskId, runId);
+      expect(readLease(taskId)?.run_id).toBe(runId);
+
+      db.tasks.advanceTaskStatus(taskId, "done");
+      expect(readLease(taskId)).toBeUndefined();
+    });
+
+    it("drops the lease when the task transitions to cancelled", () => {
+      const companyId = createTestCompany(db);
+      createTestConnector(db);
+      const workspaceId = createTestWorkspace(db, companyId);
+      const agentId = createTestAgent(db, companyId, workspaceId);
+      const taskId = createTestTask(db, companyId, agentId, workspaceId);
+      const runId = createTestRun(db, companyId, taskId, agentId, workspaceId);
+
+      db.tasks.advanceTaskStatus(taskId, "in_progress");
+      seedLease(taskId, runId);
+
+      db.tasks.advanceTaskStatus(taskId, "cancelled");
+      expect(readLease(taskId)).toBeUndefined();
+    });
+
+    it("drops the lease when the task transitions to blocked", () => {
+      const companyId = createTestCompany(db);
+      createTestConnector(db);
+      const workspaceId = createTestWorkspace(db, companyId);
+      const agentId = createTestAgent(db, companyId, workspaceId);
+      const taskId = createTestTask(db, companyId, agentId, workspaceId);
+      const runId = createTestRun(db, companyId, taskId, agentId, workspaceId);
+
+      db.tasks.advanceTaskStatus(taskId, "in_progress");
+      seedLease(taskId, runId);
+
+      db.tasks.advanceTaskStatus(taskId, "blocked");
+      expect(readLease(taskId)).toBeUndefined();
+    });
+
+    it("drops the lease when the task is bounced back to todo", () => {
+      const companyId = createTestCompany(db);
+      createTestConnector(db);
+      const workspaceId = createTestWorkspace(db, companyId);
+      const agentId = createTestAgent(db, companyId, workspaceId);
+      const taskId = createTestTask(db, companyId, agentId, workspaceId);
+      const runId = createTestRun(db, companyId, taskId, agentId, workspaceId);
+
+      db.tasks.advanceTaskStatus(taskId, "in_progress");
+      seedLease(taskId, runId);
+
+      db.tasks.advanceTaskStatus(taskId, "todo");
+      expect(readLease(taskId)).toBeUndefined();
+    });
+
+    it("leaves the lease intact when the task transitions to in_review", () => {
+      const companyId = createTestCompany(db);
+      createTestConnector(db);
+      const workspaceId = createTestWorkspace(db, companyId);
+      const agentId = createTestAgent(db, companyId, workspaceId);
+      // in_review guard requires either a reports_to or requires_user_review.
+      db.tasks.setTaskRequiresUserReview(
+        createTestTask(db, companyId, agentId, workspaceId),
+        true,
+      );
+      const taskId = createTestTask(db, companyId, agentId, workspaceId);
+      db.tasks.setTaskRequiresUserReview(taskId, true);
+      const runId = createTestRun(db, companyId, taskId, agentId, workspaceId);
+
+      db.tasks.advanceTaskStatus(taskId, "in_progress");
+      seedLease(taskId, runId);
+
+      db.tasks.advanceTaskStatus(taskId, "in_review");
+      expect(readLease(taskId)?.run_id).toBe(runId);
+    });
+  });
+
   describe("releaseTaskLease", () => {
     it("releases the lease when the runId matches", () => {
       const companyId = createTestCompany(db);