Refactor ESLint configuration and update code formatting: Standardize quotes in eslint.config.mjs, next.config.js, and various TypeScript files for consistency. Add Prettier as a dependency and include formatting scripts in package.json. Clean up unnecessary whitespace in multiple files to enhance code readability.

app/api/events/[id]/register/route.ts

@@ -139,4 +139,3 @@ export async function GET(
     return NextResponse.json({ registered: false });
   }
 }
-

app/api/events/[id]/route.ts

@@ -28,4 +28,3 @@ export async function GET(
     );
   }
 }
-

app/api/events/route.ts

@@ -18,4 +18,3 @@ export async function GET() {
     );
   }
 }
-