docs: update README, add CONTRIBUTING, expand npm keywords

Author: tintolee

.github/workflows/ci.yml

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

.github/workflows/publish.yml

@@ -0,0 +1,31 @@
+name: Publish to npm
+
+on:
+  release:
+    types: [published]
+
+permissions:
+  contents: read
+  # Required for npm Trusted Publishing (OIDC)
+  id-token: write
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    environment: npm-publish
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          registry-url: https://registry.npmjs.org
+
+      - run: npm ci
+
+      # prepublishOnly already runs lint + build + test
+      - name: Publish with provenance
+        run: npm publish --provenance --access public
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}