test(tasks): fence the background integration test on an idle owner

The rewritten test tolerated the interleaving where a fast command
settles before the running turn's next pre-step claim. The notice is
then folded into a step whose scripted reply is final, the turn closes
with an empty next-step inbox, and the collection entries are never
reached — a real timeout, not a tolerated ordering.

The command now blocks on a sentinel the test creates only after the
agent has gone idle, so the wake is the only path that can deliver the
notice, and the test asserts exactly two turns.

Also apply the review's smaller points: key the wake budget by Agent
rather than object, register the budget-refill listener only under
wakeup delivery, pin the schema default and rejection like
reportDelivery does, record the retirement-window stranding as a Known
Limitation, and cross-link the partial supersession both ways.

packages/tasks/tool-tasks/tests/tool-tasks.spec.ts

@@ -128,6 +128,13 @@ describe('tool-tasks setup', () => {
       .rejects.toThrow('waitTimeoutMs (100) exceeds maxWaitTimeoutMs (50)')
   })
 
+  it('defaults delivery to wakeup and rejects an unknown lane', () => {
+    expect(ToolTasks.Config({}).completionDelivery).toBe('wakeup')
+    expect(ToolTasks.Config({}).maxConsecutiveWakes).toBe(3)
+    expect(() => ToolTasks.Config({ completionDelivery: 'loud' as never })).toThrow()
+    expect(() => ToolTasks.Config({ maxConsecutiveWakes: 0 })).toThrow()
+  })
+
   it('rejects a wake budget that cannot bound anything', async () => {
     // Reports the load outcome as text: a resolved fiber is not safely printable.
     const loadWith = async (maxConsecutiveWakes: number): Promise<string> => {