Performance, SEO, a11y, and code quality improvements

1. Performance: 25 pages switched from force-dynamic to revalidate=300 (ISR);
   2 pages (community, developers) now fully static (SSG)
2. DB indexes: Added @@index on foreign keys for WebsiteArticles,
   WebsiteArticleReactions, WebsiteArticleComments, WebsiteHelpCenterTickets,
   WebsiteShopArticles, RadioSongRequests, StaffActivities
3. SEO: Added robots.ts, sitemap.ts, canonical URLs, Open Graph + Twitter
   Card metadata on root layout and news articles
4. A11Y: Replaced <details>/<summary> dropdowns with accessible button-based
   NavDropdown (aria-expanded, aria-haspopup, role=menu). MobileNav now
   uses translated aria-label, aria-expanded, aria-controls, role=menu
5. Code quality: Added try/catch to updateArticle/deleteArticle; deleteArticle
   now uses prisma. for atomicity
6. CI/CD: Added GitHub Actions workflow (typecheck + test)
7. i18n: Added openMenu/closeMenu keys to all 6 locales
8. Observability: Health endpoint now checks SMTP reachability when configured
9. Loading states: Added loading.tsx for root, admin, and news sections
10. Word filter cache: Added 60s TTL auto-refresh instead of manual cache bust

.github/workflows/ci.yml

@@ -0,0 +1,34 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 10
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+
+      - run: pnpm install --frozen-lockfile
+
+      - run: pnpm typecheck
+
+      - run: pnpm test
+        env:
+          SKIP_ENV_VALIDATION: true