fix(cli,hub): resolve typecheck errors in codex reasoning effort (#432)

* fix(cli,hub): resolve typecheck errors in codex reasoning effort and notification test

- Cast `getModelReasoningEffort()` return (string | null) to
  `ReasoningEffort | undefined` at three call sites in
  codexLocalLauncher.ts and runCodex.ts where the narrower type is
  expected.
- Add missing `modelReasoningEffort: null` default in
  notificationHub.test.ts to satisfy the Session type contract.

These errors were introduced in 79a13d2 and have been failing CI on
main since 2026-04-10.

* fix(cli): add missing getModelReasoningEffort to test mock session

The test stub in codexLocalLauncher.test.ts was missing the
getModelReasoningEffort method added in 79a13d2, causing runtime
TypeError in CI.

cli/src/codex/codexLocalLauncher.ts

@@ -1,5 +1,6 @@
 import { logger } from '@/ui/logger';
 import { codexLocal } from './codexLocal';
+import type { ReasoningEffort } from './appServerTypes';
 import { CodexSession } from './session';
 import { createCodexSessionScanner } from './utils/codexSessionScanner';
 import { convertCodexEvent } from './utils/codexEventConverter';
@@ -42,7 +43,7 @@ export async function codexLocalLauncher(session: CodexSession): Promise<'switch
             await codexLocal({
                 path: session.path,
                 sessionId: resumeSessionId,
-                modelReasoningEffort: session.getModelReasoningEffort() ?? undefined,
+                modelReasoningEffort: (session.getModelReasoningEffort() ?? undefined) as ReasoningEffort | undefined,
                 onSessionFound: handleSessionFound,
                 abort: abortSignal,
                 codexArgs,