ci: add CI and release workflows

CI: runs on push/PR to main, tests on Node 20 + 22 (build, typecheck, test).
Release: triggered by v* tags, runs full test suite then publishes to npm
and creates a GitHub Release with auto-generated notes.

Requires NPM_TOKEN secret for npm publish.

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

Author: pyyush

.github/workflows/ci.yml

@@ -0,0 +1,26 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [20, 22]
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: npm
+
+      - run: npm ci
+      - run: npm run build
+      - run: npm run typecheck
+      - run: npm test

.github/workflows/release.yml

@@ -0,0 +1,34 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: write
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          registry-url: https://registry.npmjs.org
+          cache: npm
+
+      - run: npm ci
+      - run: npm run build
+      - run: npm run typecheck
+      - run: npm test
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          generate_release_notes: true