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

package.json

@@ -19,8 +19,8 @@
 		"analyze": "ANALYZE=true pnpm build",
 		"test": "vitest run",
 		"test:e2e": "playwright test",
-		"lint": "eslint . --ext .ts,.tsx --max-warnings=1000",
-		"lint:fix": "eslint . --ext .ts,.tsx --fix --max-warnings=1000",
+		"lint": "eslint . --ext .ts,.tsx --max-warnings=50",
+		"lint:fix": "eslint . --ext .ts,.tsx --fix --max-warnings=50",
 		"lhci:collect": "lhci collect",
 		"lhci:assert": "lhci assert",
 		"lhci:server": "lhci server",
@@ -32,7 +32,7 @@
 	"lint-staged": {
 		"*.{js,jsx,ts,tsx}": [
 			"biome check --write",
-			"eslint --fix --max-warnings=1000"
+			"eslint --fix --max-warnings=50"
 		],
 		"*.{json,md,css,scss,html}": [
 			"biome format --write"
@@ -98,6 +98,7 @@
 		"@types/react": "^19.2.17",
 		"@types/react-dom": "^19.2.3",
 		"@types/sanitize-html": "^2.16.1",
+		"@vitest/coverage-v8": "^4.1.10",
 		"dotenv": "^17.0.0",
 		"eslint": "^10.7.0",
 		"eslint-plugin-unused-imports": "^4.4.1",