ci: add CI (typecheck/test/build) and tag-triggered npm release workflows

.github/workflows/ci.yml

@@ -0,0 +1,23 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 10
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm run typecheck
+      - run: pnpm test
+      - run: pnpm run build

.github/workflows/release.yml

@@ -0,0 +1,41 @@
+name: Release
+
+on:
+  push:
+    tags: ['v*']
+
+permissions:
+  contents: read
+  id-token: write # npm provenance / trusted publishing
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 10
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+          registry-url: https://registry.npmjs.org
+      - run: pnpm install --frozen-lockfile
+      # Skip if this version is already on the registry (idempotent re-runs)
+      - name: Check version not already published
+        id: check
+        run: |
+          NAME=$(node -p "require('./package.json').name")
+          VERSION=$(node -p "require('./package.json').version")
+          if npm view "$NAME@$VERSION" version >/dev/null 2>&1; then
+            echo "skip=true" >> "$GITHUB_OUTPUT"
+            echo "$NAME@$VERSION already published - skipping"
+          else
+            echo "skip=false" >> "$GITHUB_OUTPUT"
+          fi
+      # prepublishOnly runs typecheck + tests + build as the gate
+      - if: steps.check.outputs.skip == 'false'
+        run: npm publish --access public --provenance
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}