chore: improve tooling, linting, testing, and CI

- Add LICENSE file (CC BY-NC-SA 4.0)
- Add .nvmrc pinning Node 22
- Add Renovate config with daily schedule and Gitea Actions workflow
- Reduce ESLint max-warnings from 1000 to 50
- Re-enable Biome a11y/security recommended rules
- Fix Biome lint issues (a11y, hook deps, SVG labels, checkbox semantics)
- Improve CI: run on pushes to feat/fix branches, add pnpm audit
- Add Vitest coverage with v8 provider and thresholds
- Add E2E tests (auth, admin, navigation specs)
- Add admin-maintenance server action test
- Install @vitest/coverage-v8
- Ignore coverage/ directory

src/components/top-header.tsx

@@ -220,6 +220,8 @@ export async function TopHeader({ session }: { session: Session | null }) {
 							strokeLinecap="round"
 							strokeLinejoin="round"
 							style={{ color: textColor }}
+							role="img"
+							aria-label="Notifications"
 						>
 							<path d="M6 8a6 6 0 0 1 12 0c0 7 3 9 3 9H3s3-2 3-9" />
 							<path d="M10.3 21a1.94 1.94 0 0 0 3.4 0" />