ci: reduce redundant workflow work

[NWYLZW]

Summary

• Reduce redundant CI work while preserving the required validation and Merge Queue gates.
• Quality no longer repeats the same full validation on main after Merge Queue.
• N/A matrix tasks avoid checkout except docs-only lint; FFmpeg reuses the runner install when present.
• setup-workspace restores the exact workspace cache before redundant pnpm-store setup.
• PWA Production uses the tested recursive client workspace closure and no longer self-triggers on workflow-only edits.

Changelog

• Changelog path or "Not applicable": Not applicable (CI/CD optimization only).

Screenshots

Not applicable

Validation

• 64/64 targeted tests pass.
• Full six-scope typecheck passes.
• Full ESLint passes.
• Client Vite production build passes.
• Production dependency audit passes.
• dprint, YAML parse, and git diff checks pass.
• Full repository Vitest has unrelated local config/timing baseline failures and is not claimed as green.

Review Scope

• Risk: medium
• Applicable profiles: workflow, action, script tests, policy/CI behavior
• Evidence: Independent review PASS after closing two P1 findings; Accepted Feedback Learning and Experience Review PASS.
• Rule exceptions: none

Rollback

Revert this commit to restore the prior workflow and action behavior. If an individual workflow or action change causes an incident, revert the corresponding file change and rerun the required validation before merging the rollback.

Release Tags was intentionally left unchanged after review.

Experience Review

• 已判断是否需要沉淀经验
• 如需要，已运行 $post-task-experience-review
• reviewer PASS / NOT APPLICABLE 后才进入 merge

Policy Conflict Review

• Independent read-only reviewer checked workflow, permission, and release-rule conflicts and reported PASS

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
oneworks-dev	Ready	Preview	Aug 22, 2026 7:09am

[github-actions]

Experience Review

Before merge, make sure the PR body contains this completed checklist:

## Experience Review
- [x] 已判断是否需要沉淀经验
- [x] 如需要，已运行 `$post-task-experience-review`
- [x] reviewer `PASS` / `NOT APPLICABLE` 后才进入 merge

Checklist to confirm:

• Decide whether this PR produced reusable project experience.
• If experience should be captured, run $post-task-experience-review.
• Merge only after the independent reviewer reports PASS or NOT APPLICABLE for the Experience Review Result.
• For workflow, permission, or release-rule documentation changes, also add this checked section to the PR body after an independent read-only conflict review:

## Policy Conflict Review
- [x] Independent read-only reviewer checked workflow, permission, and release-rule conflicts and reported PASS