Migrate to release-please for automated versioning and releases

[DrumRobot]

Problem

Currently, the release version must be manually determined (pnpm version patch/minor), requiring manual analysis of the commit history to decide the appropriate bump type. Since the project already follows Conventional Commits, this can be automated.

Current Release Flow

Manual decision: pnpm version patch|minor|major
  → git tag v0.4.x
  → git push origin v0.4.x
  → GitHub Actions (publish-npm.yml / release-vscode.yml) auto-deploy

Why release-please

Tool	Stars	Automation	Fit
semantic-release	~23k	Fully automatic	Overkill for current scale
Changesets	~11.6k	Changeset files per change	Extra manual step per PR
release-please	~6.8k	PR-based review workflow	Best fit — matches current review-then-release process
Cocogitto	~1k	CLI cog bump	Less GitHub integration

Star history

Chosen: release-please — PR-based workflow (auto-generates Release PR → user reviews → merge triggers tag+release) aligns with project's manual review before publish pattern. Google-maintained, Apache-2.0.

Proposed Flow

Commits land on main (Conventional Commits)
  → release-please auto-creates/updates "Release PR"
     (bumps version, updates CHANGELOG.md)
  → User reviews Release PR
  → Merge → release-please creates git tag + GitHub Release
  → Existing publish-npm.yml / release-vscode.yml triggered by tag

Monorepo Considerations

• release-please supports manifest mode for monorepos
• npm packages (core, web, mcp): grouped release via root pnpm version
• vscode-extension: independent release cycle (vscode-v* tags) — separate release-please config or excluded

Commit Type → Version Mapping

Commit Type	Bump
feat	minor
fix, perf	patch
BREAKING CHANGE	major
docs, style, refactor, test, chore, ci	none

Checklist

• Add release-please-config.json and .release-please-manifest.json
• Create .github/workflows/release-please.yml workflow
• Configure monorepo manifest (core/web/mcp grouped, vscode-extension separate or excluded)
• Integrate with existing publish-npm.yml tag trigger
• Remove or replace suggest-version.yml (PR ci: add suggest-version workflow for automated version calculation #129)
• Test: merge a feat: commit → Release PR auto-created with minor bump
• Test: merge Release PR → tag created → publish workflow triggered
• Verify release-please correctly bumps major on feat!: commit (smoke test from PR ci: add suggest-version workflow for automated version calculation #129 review)
• Configure bootstrap-sha / initial-version for first run before any v* tag exists (from PR ci: add suggest-version workflow for automated version calculation #129 review)
• Verify multi-category commit dedup — feat!: produces one entry per package (from PR ci: add suggest-version workflow for automated version calculation #129 review)

Verification

• Merge a feat: commit to main → Release PR appears with correct version bump and CHANGELOG
• Merge a fix: commit → Release PR updates with patch bump
• Merge Release PR → git tag v0.x.x created → publish-npm.yml triggers automatically
• Only docs:/test: commits → no Release PR created

Note: PR #129 (manual commit counting approach) will be superseded by this migration.