* feat: add API key management UI
- Created settings page for users to create, view, and delete API keys
- Added Settings link to app navigation header
- Fixed delete operation return value handling in backend to properly handle asyncpg's None response
* feat: replace browser confirm with dialog for API key deletion
- Added Chakra UI Dialog component for better UX when confirming API key deletion
- Implemented proper focus management with cancelRef for accessibility
- Replaced native browser confirm() with controlled dialog state
* style: format API keys page with consistent line breaks
* feat: auto-select API key text for easier copying
- Added automatic text selection after API key creation to streamline the copy workflow
- Applied className to Code component for DOM targeting
* feat: improve API keys page layout and responsiveness
- Reduced max width from 1200px to 800px for better readability
- Added explicit width constraint to ensure consistent sizing across viewports
* refactor: remove redundant comments from API keys page
