fix(docs): address Codex review round 1 on the AGENTS.md rewrite

- Restore the universal JSDoc rule the rewrite dropped (module doc
  comment + semantic JSDoc on every export), in root AGENTS.md § Type
  safety and documentation — the generated-catalog RFC cites it as the
  rule the generator enforces at the source.
- Repoint the six remaining citations of moved content that the
  section-name grep missed (rule-title quotes and prose references):
  agent-loop agent.ts, acp index.ts, acp turns.spec.ts, the Exa e2e
  header, the real-api-e2e RFC, the doc-sync-enforcement RFC amendment,
  and rfc/implemented/AGENTS.md's section-name casing.
- Fix two docs/testing.md overstatements: the unit tier also runs
  examples/*/tests specs, and keyless-by-nature examples have no
  with-key smoke.
- Displacement trims keep root AGENTS.md at 1,498/1,500.

packages/core/agent-loop/src/agent.ts

@@ -79,7 +79,7 @@ export class ReactLoopAgent implements Agent {
     // Release quiescence waiters on a transition OUT of running BEFORE emitting
     // (the disposer handles the disposed transition separately). Settling first
     // means a throwing `agent/status` subscriber cannot starve a `whenIdle()`
-    // waiter (AGENTS.md "contain callback exceptions" — a lifecycle await must
+    // waiter (docs/defensive-patterns.md "contain callback exceptions" — a lifecycle await must
     // not hang on one bad listener).
     if (status !== 'running') this.settleIdleWaiters()
     try {