chore: add release preparation skill (#368)

Author: pavelfeldman

.claude/skills/dev/SKILL.md

@@ -6,3 +6,4 @@ description: Development workflows for the playwright-cli repository. Use when t
 # Development skills
 
 * **Rolling Playwright dependency** [roll.md](roll.md)
+* **Preparing Release** [release.md](release.md)

.claude/skills/dev/release.md

@@ -0,0 +1,77 @@
+# How to prepare a release
+
+A release is a `chore: mark v<next-patch>` commit whose PR body is the release notes. Example: https://github.com/microsoft/playwright-cli/pull/367.
+
+## Steps
+
+1. **Bump the patch version** in `package.json` (e.g. `0.1.7` → `0.1.8`), then `npm install` to sync `package-lock.json`. This is the entry point — everything else (branch name, PR title, release notes filename) keys off the new version.
+
+2. **Find the baseline.** The previous release is the last `chore: mark v...` commit on `main`. Read the Playwright version pinned at that commit — that's the baseline for the diff.
+   ```bash
+   git log --oneline | grep "mark v" | head -1
+   git show <sha>:package.json | grep '"playwright"'
+   ```
+
+3. **Figure out the playwright commit window.** Convert the baseline's alpha timestamp to a UTC date, and use the new alpha's date as the upper bound. Alphas are either `1.X.0-alpha-<ms-epoch>` or `1.X.0-alpha-<YYYY-MM-DD>`.
+   ```bash
+   date -u -d @<seconds> '+%Y-%m-%d %H:%M:%S UTC'   # for ms-epoch, divide by 1000 first
+   ```
+
+4. **List Playwright commits in the window.** Run from `~/code/playwright` (a local Playwright checkout). `--after` / `--before` work on any ref regardless of what `origin/main` currently points at; `--since` / `--until` can silently return empty if the branch is behind.
+   ```bash
+   cd ~/code/playwright && git log --after='<baseline-date>' --before='<new-date>' --pretty=format:'%h %ci %s'
+   ```
+
+5. **Filter to CLI-relevant commits.** Keep anything touching the CLI surface or its runtime; drop internal/unrelated churn.
+   - **Keep:** `src/tools/cli-client/**`, `src/tools/cli-daemon/**`, `src/tools/mcp/**`, `remote/playwrightConnection`, CDP-attach paths, tracing/video APIs the CLI exposes, and anything with a `fix(cli)` / `feat(cli)` / `fix(mcp)` / `feat(mcp)` prefix.
+   - **Drop:** test-runner rolls, firefox/chromium/webkit version bumps, docs-only, test infra, unrelated refactors.
+   - Use `git show --stat <sha>` to sanity-check whether a commit's files touch the CLI.
+
+6. **Pull issue context for each kept PR.** The PR's linked issue often has better user-facing wording than the PR/commit title.
+   ```bash
+   gh pr view <pr> --repo microsoft/playwright --json title,body,closingIssuesReferences
+   gh issue view <issue> --repo microsoft/playwright-cli --json title,body,state
+   ```
+
+7. **Write the release notes** to `RELEASE_NOTES_v<version>.md`. Use this exact shape — **no top-level `#` header**, the PR title is the heading:
+
+   ```markdown
+   ## Highlights
+
+   - **<issue wording, not commit wording>** ([#<issue>](https://github.com/microsoft/playwright-cli/issues/<issue>)) — one sentence on the user-facing effect. ([microsoft/playwright#<pr>](https://github.com/microsoft/playwright/pull/<pr>))
+
+   ## Fixes
+
+   - `<commit subject>` — what changed and why it matters. ([#<pr>](https://github.com/microsoft/playwright/pull/<pr>))
+
+   ## Upgrading
+
+   ```bash
+   npm install -g @playwright/cli@<version>
+   ```
+   ```
+
+   Wording rules:
+   - **Highlights lead with the user-reported problem from the linked issue**, not the commit subject. Drop internal terms (`cdpPort`, `tombstones`) from highlight bullets.
+   - Only list things that change user-visible behavior. Skip internal cleanups unless they have a user-facing effect.
+   - Reference both the playwright-cli issue (if any) and the microsoft/playwright PR.
+
+8. **Commit, push, open PR.** The PR body is the contents of the release notes file (no `#` header, no filename).
+   ```bash
+   git checkout -b mark-v<version>
+   git add package.json package-lock.json
+   git commit -m "chore: mark v<version>"
+   git push -u origin mark-v<version>
+   gh pr create --repo microsoft/playwright-cli \
+     --head pavelfeldman:mark-v<version> \
+     --base main \
+     --title "chore: mark v<version>" \
+     --body "$(cat RELEASE_NOTES_v<version>.md)"
+   ```
+
+## Pitfalls
+
+- **Don't use `--since` / `--until`** when diffing Playwright — if `origin/main` in the local checkout is behind, they return empty. `--after` / `--before` against the local ref work.
+- **Don't include a `# playwright-cli vX.Y.Z` header** in the PR body — GitHub already renders the PR title.
+- **Don't paraphrase the commit subject as the highlight.** A user who filed an issue described the pain; reuse their framing.
+- **Don't include test-runner / browser-version-roll commits** in release notes — they're noise for CLI users.

CLAUDE.md

@@ -0,0 +1,30 @@
+## Commit Convention
+
+Semantic commit messages: `label(scope): description`
+
+Labels: `fix`, `feat`, `chore`, `docs`, `test`, `devops`
+
+```bash
+git checkout -b fix-39562
+# ... make changes ...
+git add <changed-files>
+git commit -m "$(cat <<'EOF'
+fix(proxy): handle SOCKS proxy authentication
+
+Fixes: https://github.com/microsoft/playwright/issues/39562
+EOF
+)"
+git push origin fix-39562
+gh pr create --repo microsoft/playwright --head username:fix-39562 \
+  --title "fix(proxy): handle SOCKS proxy authentication" \
+  --body "$(cat <<'EOF'
+## Summary
+- <describe the change very! briefly>
+
+Fixes https://github.com/microsoft/playwright/issues/39562
+EOF
+)"
+```
+
+Never add Co-Authored-By agents in commit message.
+Branch naming for issue fixes: `fix-<issue-number>`