test: fix assertions broken by runContext propagation

store.logEntry, assignTask, and checkoutTask now receive an extra
runContext argument. Updated test assertions in executor.test.ts,
agent-heartbeat.test.ts, and restart.integration.test.ts to match
the current call signatures using expect.objectContaining where
appropriate.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/engine/src/restart.integration.test.ts

@@ -943,6 +943,8 @@ describe("Worktree pool restart with recycleWorktrees=true", () => {
     expect(store.logEntry).toHaveBeenCalledWith(
       "FN-110",
       expect.stringContaining("Acquired worktree from pool"),
+      undefined,
+      expect.objectContaining({ agentId: "executor" }),
     );
   });