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/web/web-search-exa/tests/exa.e2e.ts

@@ -3,7 +3,7 @@ import { ExaSearchProvider, EXA_DEFAULT_BASE_URL, EXA_DEFAULT_HIGHLIGHTS_PER_RES
 
 /**
  * Real-API smoke for the Exa search provider. Self-skips without `$EXA_API_KEY`
- * (CI has no secrets), per the with-key e2e policy in AGENTS.md § Secrets.
+ * (CI has no secrets), per the with-key e2e policy in docs/testing.md.
  */
 const apiKey = process.env.EXA_API_KEY
 const maybe = apiKey !== undefined && apiKey.length > 0 ? describe : describe.skip