feat: add API key management UI (#716)

* 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

www/app/(app)/layout.tsx

@@ -78,6 +78,14 @@ export default async function AppLayout({
           )}
           {featureEnabled("requireLogin") ? (
             <>
+              &nbsp;·&nbsp;
+              <Link
+                href="/settings/api-keys"
+                as={NextLink}
+                className="font-light px-2"
+              >
+                Settings
+              </Link>
               &nbsp;·&nbsp;
               <UserInfo />
             </>