chore(ci): consolidate publish into release-please workflow (#37)

## Summary
- Add `workflow_dispatch` trigger to `release-please.yml` for manual
re-publishes
- Remove separate `publish.yml` (npm only allows one trusted publisher
per package)
- Manual trigger: `gh workflow run release-please.yml -f tag=v1.0.3`

## Test plan
- [ ] CI passes
- [ ] After merge: trigger manual publish for v1.0.3

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

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: marcstraube

.github/workflows/publish.yml

@@ -4,6 +4,11 @@ on:
   push:
     branches:
       - master
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: 'Publish an existing release tag (e.g. v1.0.3)'
+        required: true
 
 permissions:
   contents: write
@@ -12,6 +17,7 @@ permissions:
 
 jobs:
   release-please:
+    if: github.event_name == 'push'
     runs-on: ubuntu-latest
     steps:
       - uses: googleapis/release-please-action@v4
@@ -59,3 +65,41 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: gh release upload ${{ steps.release.outputs.tag_name }} sbom.cdx.json --clobber
+
+  publish:
+    if: github.event_name == 'workflow_dispatch'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+        with:
+          ref: ${{ inputs.tag }}
+
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v5
+        with:
+          version: 10
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '20'
+          cache: 'pnpm'
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Build package
+        run: pnpm run build
+
+      - name: Publish to npm
+        run: pnpm publish --access public --no-git-checks --provenance
+
+      - name: Generate SBOM
+        run: pnpm run sbom
+
+      - name: Upload SBOM to release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: gh release upload ${{ inputs.tag }} sbom.cdx.json --clobber