fix(acp): address Codex review — strict ctx.get, correct fiber-ownership doc + test

- AgentLoop.resume uses `this.ctx.get('sessionPersistence')` (strict) instead
  of the `, false` overload: still topology-independent, but an inactive/
  absent backend reads as undefined (rejected by the existing guard) rather
  than being handed back mid-teardown.
- Correct the bridge teardown comment: an ACP-created agent's registry entry
  binds to the BRIDGE fiber (the factory is reached through the bridge's
  traceable proxy, so AgentLoop.start's `this.ctx.effect` registration uses the
  caller context), not the AgentLoop fiber — so an ACP-only HMR dispose
  reclaims it. Add a regression test pinning that ownership.
- Sync the ctx.get guidance in the post-mortem, packages/AGENTS.md, and the
  dsh-code-review skill to the strict form.

.agents/skills/dsh-code-review/SKILL.md

@@ -40,7 +40,7 @@ These come straight from the source docs above. They are not discretionary; abse
 Where your independent reasoning earns its keep. Start here, then keep going across the broader aspects above.
 
 - **e2e verifies the world, not the agent's self-report.** For real-API tests, confirm the assertion re-runs the command/checks the file externally — a keyword probe lets a cheating agent pass (see AGENTS.md e2e bullet). For a behavior change to the agent's real flows, a no-key/mock test alone is usually insufficient: a with-key e2e (especially a smoke test that boots the real example and checks the world) is cheap here and catches "green units, broken product" — encourage it rather than treating real-API tests as expensive (see AGENTS.md § Secrets / .env).
-- **Plugin export shape + real-loader coverage.** A new/changed `cordis.yml`-loaded plugin: is it a function/namespace plugin (`name`/`inject`/`Config`/`apply` named exports) with NO `export default`? A stray default export makes the Loader's `unwrapExports` drop `inject` and the plugin crashes at load with `cannot get property … without inject` — invisible to hand-built `ctx.plugin({...})` tests and to line coverage. Confirm there's a test driving it through the REAL loader path (the no-key subprocess e2e for ACP is the model). And any opportunistic read of a service NOT in `static inject` should use `ctx.get(name, false)`, not `ctx.<name>` (the property proxy throws through a foreign shadow). See [packages/AGENTS.md](../../../packages/AGENTS.md) and [docs/postmortem/0001](../../../docs/postmortem/0001-acp-default-export-drops-inject.md).
+- **Plugin export shape + real-loader coverage.** A new/changed `cordis.yml`-loaded plugin: is it a function/namespace plugin (`name`/`inject`/`Config`/`apply` named exports) with NO `export default`? A stray default export makes the Loader's `unwrapExports` drop `inject` and the plugin crashes at load with `cannot get property … without inject` — invisible to hand-built `ctx.plugin({...})` tests and to line coverage. Confirm there's a test driving it through the REAL loader path (the no-key subprocess e2e for ACP is the model). And any opportunistic read of a service NOT in `static inject` should use `ctx.get(name)`, not `ctx.<name>` (the property proxy throws through a foreign shadow). See [packages/AGENTS.md](../../../packages/AGENTS.md) and [docs/postmortem/0001](../../../docs/postmortem/0001-acp-default-export-drops-inject.md).
 - **Seam discipline.** New swappable capability? Check it's split per the capability-seams RFC (interface / impl / consumer), and that the consumer injects the interface key, never an implementation type.
 - **Test quality.** A test that passes but asserts the wrong thing is worse than none. Check that new tests would actually fail if the behavior regressed, and that they exercise the contract (events fired, disposal reached) rather than restating the implementation.
 - **Intent and contracts.** Does the change do what the PR says, and honor the documented contract on *both* sides of every seam it touches (see AGENTS.md "Honor cross-seam contracts on BOTH sides")?