ci: add GitHub Actions workflow for unit and E2E tests

Runs build, Vitest unit tests, and Playwright E2E tests on push/PR
to main and develop branches.

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

Author: srsholmes

.github/workflows/ci.yml

@@ -0,0 +1,76 @@
+name: CI
+
+on:
+  push:
+    branches: [main, develop]
+  pull_request:
+    branches: [main, develop]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build library
+        run: npm run rollup
+
+  unit-tests:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run unit tests
+        run: npm test
+
+  e2e-tests:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build library
+        run: npm run rollup
+
+      - name: Install example dependencies
+        run: npm ci
+        working-directory: example
+
+      - name: Install Playwright browsers
+        run: npx playwright install chromium --with-deps
+
+      - name: Run E2E tests
+        run: npm run test:e2e
+
+      - name: Upload test results
+        if: ${{ !cancelled() }}
+        uses: actions/upload-artifact@v4
+        with:
+          name: playwright-report
+          path: test-results/
+          retention-days: 7