feat: add HLS playback support with hls.js

- viewer.js: dynamic hls.js loading, HLS-aware panel creation, error handling
- schema.json: hlsManifest and mediaType fields (optional, backward compatible)
- types.ts: VideoEntry interface with MediaType type
- isHls() null guard fix
- tests: 39 tests (schema, viewer units, data flow, integration)
- CI: GitHub/Gitea Actions workflow (npm test on push/PR)
- deps: ajv, ajv-formats, jsdom for testing

.github/workflows/ci.yml

@@ -0,0 +1,24 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test