test(server): verify retention resume at its retained deadline

Co-Authored-By: Paperclip <noreply@paperclip.ing>

doc/plans/2026-10-25-voice-drain-repair.md

@@ -50,3 +50,13 @@ then verifies the saved reply sends on resume without another producer.
 
 All later shared-worker consumers inherit this repair through the stack. Their
 combined-tip checks and PR checks still need fresh verification after propagation.
+
+## Retention resume assertion
+
+The combined-tip consumer run exposed a retention test that called flush after
+resume and assumed a zero activity counter meant the retained retry had run. Its
+helper checks active work only; zero is now also the correct paused state. The
+owner test now advances the actual retained nextWakeAt, waits for row removal,
+and checks disarm. Before resume it also proves a stable idle snapshot through a
+minute of quiet. All 11 retention cases pass in /tmp/sleep24-drain-tests.log.
+No production scheduling deadline or dispatch behavior changed for this repair.

server/src/__tests__/voice-inbound-retention.test.ts

@@ -151,8 +151,13 @@ const support = external ? { supported: true } : await getEmbeddedPostgresTestSu
   });
   it("keeps the first write during drain and runs it on resume", async () => {
     await start(); await flush(); enabled = false;
-    const call = await admission(); await quiet(60_000); expect(await row(call.id)).toBeDefined();
-    enabled = true; await flush(); expect(await row(call.id)).toBeUndefined(); await quiet();
+    const call = await admission(); await flush();
+    const drained = idleWorkSnapshot();
+    await quiet(60_000); expect(idleWorkSnapshot()).toEqual(drained); expect(await row(call.id)).toBeDefined();
+    const resumeAt = coordinator!.nextWakeAt(); expect(resumeAt).not.toBeNull();
+    enabled = true; await vi.advanceTimersByTimeAsync(Math.max(0, resumeAt! - Date.now()));
+    await vi.waitFor(async () => { await flush(); expect(await row(call.id)).toBeUndefined(); });
+    expect(coordinator!.nextWakeAt()).toBeNull(); await quiet();
   });
   it("pages through more than one batch of history across companies", async () => {
     for (let i = 0; i < 104; i++) await admission();