feat(cache-warming): consume CR-4 lifecycle — tab-close cancel + scope-aware subscriptions

- closeTab now POSTs /conversations/:id/close (abort in-flight turn + stop/disable
  warming server-side); disconnect still leaves both running ([email protected])
- syncSubscriptions honors catalog scope ([email protected]): global surfaces are
  not re-subscribed on conversation switch
- fix(ws): the surface-message parser dropped the conversationId echo (CR-4d was
  ours, not the backend's) — preserved + unit-tested
- secondsUntilNext: 3s stale guard — a past nextWarmAt renders as waiting, not 0s
- re-pinned + re-mirrored [email protected] / [email protected]
- scripts/probe-cache-warming.ts: live CR-4 probe (default-off, future nextWarmAt,
  repeated warms, mid-turn close abort, idempotent re-close) — 17/17 against bin/up

1 files changed, 9 insertions, 1 deletions

diff --git a/src/features/cache-warming/logic/view-model.test.ts b/src/features/cache-warming/logic/view-model.test.ts
index 3d6f6d0..d5ea901 100644
--- a/src/features/cache-warming/logic/view-model.test.ts
+++ b/src/features/cache-warming/logic/view-model.test.ts
@@ -215,6 +215,14 @@ describe("secondsUntilNext (authoritative, from nextWarmAt)", () => {
 		expect(secondsUntilNext(10_000, 10_000)).toBe(0);
 		expect(secondsUntilNext(250_000, 10_000)).toBe(240);
 		expect(secondsUntilNext(70_000, 10_000)).toBe(60);
-		expect(secondsUntilNext(5_000, 999_999)).toBe(0); // already past
+	});
+
+	it("treats a nextWarmAt past the stale grace as not scheduled (belt-and-braces)", () => {
+		// Within the 3s grace an on-time warm may briefly read "0s"…
+		expect(secondsUntilNext(10_000, 11_000)).toBe(0);
+		expect(secondsUntilNext(10_000, 13_000)).toBe(0);
+		// …but beyond it the value is stale → null (the "waiting…" state).
+		expect(secondsUntilNext(10_000, 13_001)).toBeNull();
+		expect(secondsUntilNext(5_000, 999_999)).toBeNull();
 	});
 });