ci: add Dependabot, security audit, release-please, and CI optimization (#64)

* chore(ci): add Dependabot for npm and GitHub Actions updates

- Weekly npm dependency updates with PR limit of 10
- Weekly GitHub Actions version updates with PR limit of 5
- Conventional commit prefixes (chore(deps), chore(ci))

* ci: add security audit workflow

- Run npm audit on push/PR and weekly schedule
- Fail on high-severity vulnerabilities using audit-ci
- Only audit production dependencies

* ci: add release-please for automated changelog and versioning

- Auto-generate CHANGELOG.md from Conventional Commits
- Create version bump PRs on push to main
- Works alongside existing release.yml for npm publish

* ci: add concurrency controls and Node.js version matrix

- Add concurrency groups to ci, e2e-headed, security workflows
  to cancel duplicate runs on the same branch
- Test unit tests across Node 18/20/22 with fail-fast: false
- Update test step name to show Node version

* chore: bump minimum Node.js version from 18 to 20

- Update engines.node in package.json to >=20.0.0
- Update prerequisites in README.md and README.zh-CN.md
- Remove Node 18 from CI test matrix

* review: fix release token and prod-only audit scope

* docs: align Node 20 troubleshooting guidance

---------

Co-authored-by: jackwener <jakevingoo@gmail.com>

.github/dependabot.yml

@@ -0,0 +1,27 @@
+version: 2
+
+updates:
+  # npm dependencies
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    open-pull-requests-limit: 10
+    labels:
+      - "dependencies"
+    commit-message:
+      prefix: "chore(deps)"
+
+  # GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    open-pull-requests-limit: 5
+    labels:
+      - "dependencies"
+      - "ci"
+    commit-message:
+      prefix: "chore(ci)"

.github/workflows/ci.yml

@@ -9,6 +9,10 @@ on:
     - cron: '0 8 * * 1'  # Weekly Monday 08:00 UTC — smoke tests
   workflow_dispatch:
 
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   # ── Fast gate: typecheck + build ──
   build:
@@ -34,20 +38,22 @@ jobs:
   unit-test:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
+        node-version: ['20', '22']
         shard: [1, 2]
     steps:
       - uses: actions/checkout@v4
 
       - uses: actions/setup-node@v4
         with:
-          node-version: '22'
+          node-version: ${{ matrix.node-version }}
           cache: 'npm'
 
       - name: Install dependencies
         run: npm ci
 
-      - name: Run unit tests (shard ${{ matrix.shard }}/2)
+      - name: Run unit tests (Node ${{ matrix.node-version }}, shard ${{ matrix.shard }}/2)
         run: npx vitest run src/ --reporter=verbose --shard=${{ matrix.shard }}/2
 
   # ── Smoke tests (scheduled / manual only) ──

.github/workflows/e2e-headed.yml

@@ -7,6 +7,10 @@ on:
     branches: [main, dev]
   workflow_dispatch:
 
+concurrency:
+  group: e2e-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   e2e-headed:
     runs-on: ubuntu-latest

.github/workflows/release-please.yml

@@ -0,0 +1,25 @@
+name: Release Please
+
+on:
+  push:
+    branches: [main]
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Ensure release-please token is configured
+        run: |
+          if [ -z "${{ secrets.RELEASE_PLEASE_TOKEN }}" ]; then
+            echo "RELEASE_PLEASE_TOKEN secret is required so release PRs can trigger downstream CI workflows." >&2
+            exit 1
+          fi
+
+      - uses: googleapis/release-please-action@v4
+        with:
+          release-type: node
+          token: ${{ secrets.RELEASE_PLEASE_TOKEN }}

.github/workflows/security.yml

@@ -0,0 +1,36 @@
+name: Security Audit
+
+on:
+  push:
+    branches: [main, dev]
+  pull_request:
+    branches: [main, dev]
+  schedule:
+    - cron: '0 9 * * 1'  # Weekly Monday 09:00 UTC
+
+permissions:
+  contents: read
+
+concurrency:
+  group: security-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: npm audit (production)
+        run: npm audit --omit=dev --audit-level=high
+
+      - name: Check for known vulnerabilities
+        run: npx --yes audit-ci@^7 --high --skip-dev