fix(x): FakeTurnEventBus satisfies ITurnEventBus

The interface grew subscribe/subscribeAll when the IPC bridge moved
to resolving ITurnEventBus, but the runtime-test fake still only had
publish — a TS2739 invisible to vitest and the build tsconfig. The
fake now declares 'implements ITurnEventBus' so the next interface
change fails loudly here instead of silently drifting.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/x/packages/core/src/runtime/turns/runtime.test.ts

@@ -15,6 +15,7 @@ import type { IAgentResolver } from "./agent-resolver.js";
 import type { TurnExecution, TurnOutcome } from "./api.js";
 import { TurnDependencyError, TurnInputError } from "./api.js";
 import type { TurnLifecycleEvent } from "./bus.js";
+import type { ITurnEventBus } from "./event-hub.js";
 import { TurnRepoContextResolver } from "./context-resolver.js";
 import { InMemoryTurnRepo } from "./in-memory-turn-repo.js";
 import type {
@@ -278,11 +279,17 @@ class FakeBus {
     }
 }
 
-class FakeTurnEventBus {
+class FakeTurnEventBus implements ITurnEventBus {
     events: TurnBusEvent[] = [];
     publish(event: TurnBusEvent): void {
         this.events.push(event);
     }
+    subscribe(): () => void {
+        return () => {};
+    }
+    subscribeAll(): () => void {
+        return () => {};
+    }
 }
 
 class FakeIdGen {