docs: add application modernization plan (#71528)

* docs: add application modernization plan

* docs: clarify frontend skill target

docs/help/gpt54-codex-agentic-parity-maintainers.md

@@ -149,6 +149,28 @@ The parity harness is not the only evidence source. Keep this split explicit in
 - PR D owns the scenario-based GPT-5.4 vs Opus 4.6 comparison
 - PR B deterministic suites still own auth/proxy/DNS and full-access truthfulness evidence
 
+## Quick maintainer merge workflow
+
+Use this when you are ready to land a parity PR and want a repeatable, low-risk sequence.
+
+1. Confirm evidence bar is met before merge:
+   - reproducible symptom or failing test
+   - verified root cause in touched code
+   - fix in the implicated path
+   - regression test or explicit manual verification note
+2. Triage/label before merge:
+   - apply any `r:*` auto-close labels when the PR should not land
+   - keep merge candidates free of unresolved blocker threads
+3. Validate locally on the touched surface:
+   - `pnpm check:changed`
+   - `pnpm test:changed` when tests changed or bug-fix confidence depends on test coverage
+4. Land with the standard maintainer flow (`/landpr` process), then verify:
+   - linked issues auto-close behavior
+   - CI and post-merge status on `main`
+5. After landing, run duplicate search for related open PRs/issues and close only with a canonical reference.
+
+If any one of the evidence bar items is missing, request changes instead of merging.
+
 ## Goal-to-evidence map
 
 | Completion gate item                     | Primary owner | Review artifact                                                     |