Add API key authentication for external access

- Create API key context for managing authentication state
- Add dedicated settings page for API key management
- Move performance metrics to dedicated page in navigation
- Update middleware to support URL parameter fallback
- Enhance UI with proper glass morphism styling
- Add Solarized color utilities to CSS
- Improve spacing and padding throughout UI components
- Remove manual bullet points from list items

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

middleware.ts

@@ -8,8 +8,8 @@ export function middleware(request: NextRequest) {
       return NextResponse.next();
     }
 
-    // Check for API key in header
-    const apiKey = request.headers.get('x-api-key');
+    // Check for API key in header or URL parameter
+    const apiKey = request.headers.get('x-api-key') || request.nextUrl.searchParams.get('apikey');
     const validKey = process.env.API_KEY;
 
     // If API_KEY is not set in environment, skip authentication (development mode)