Implement authentication phase with Cidaas OAuth2 integration

- Add authentication middleware to protect routes
- Create API endpoints for login, logout, registration, and user info
- Develop UI components for login and registration forms
- Integrate VeeValidate for form validation
- Update environment configuration for Cidaas settings
- Add i18n support for English and German languages
- Enhance Tailwind CSS for improved styling of auth components
- Document authentication flow and testing procedures

.claude/settings.local.json

@@ -40,7 +40,11 @@
       "Bash(pnpm db:studio:*)",
       "Bash(docker exec:*)",
       "Bash(git add:*)",
-      "Bash(git commit:*)"
+      "Bash(git commit:*)",
+      "Bash(npx shadcn-nuxt@latest add:*)",
+      "Bash(pnpm exec nuxi:*)",
+      "mcp__context7__get-library-docs",
+      "mcp__playwright__browser_click"
     ],
     "deny": [],
     "ask": []