security: add CI workflow to build dist/ after merge (#12)

* security: add CI workflow to build dist/ after merge

Phase 1 of removing dist/ from PRs to close security attack vector.

Changes:
- Add build-dist.yml workflow that builds and commits dist/ on push to main
- Update CONTRIBUTING.md with build process documentation
- Reset CHANGELOG.md to 0.0.1 (initial release)

After this is verified working, Phase 2 will remove dist/ from git tracking.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: prevent CI re-trigger on dist/ changes

Add paths-ignore for dist/** to ci.yml so CI doesn't re-run when
build-dist workflow commits compiled output. Addresses race condition.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: add concurrency, permissions, and build verification

Address review feedback:
- Add concurrency group to queue builds (prevents race conditions)
- Add explicit contents: write permission
- Add build verification step (test -f dist/index.js)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: run tests before building dist/

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/build-dist.yml

@@ -0,0 +1,42 @@
+name: Build dist
+
+on:
+  push:
+    branches: [main]
+
+concurrency:
+  group: build-dist
+  cancel-in-progress: false
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    if: "!contains(github.event.head_commit.message, '[auto]')"
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - run: npm ci
+      - run: npm test
+      - run: npm run build
+
+      - name: Verify build output
+        run: test -f dist/index.js || exit 1
+
+      - name: Commit dist/
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add dist/ --force
+          git diff --staged --quiet || git commit -m "build: compile dist/ [auto]"
+          git push

.github/workflows/ci.yml

@@ -4,6 +4,8 @@ on:
   pull_request:
   push:
     branches: [main]
+    paths-ignore:
+      - 'dist/**'
 
 jobs:
   test: