Enhance date formatting in UptimeStatusIsland and ensure UTC compliance in API

- Improved the formatLocalTime function to handle various date formats and ensure accurate timezone conversion.
- Updated the ensureUTC function to check for ISO format and append 'Z' for UTC interpretation when necessary.

src/pages/api/uptime.ts

@@ -58,7 +58,13 @@ const fetchWithTimeout = async (url: string, options: RequestInit, timeout = 100
 
 // Helper function to ensure a date string is in UTC ISO format
 function ensureUTC(dateString: string): string {
-  const date = new Date(dateString);
+  // If it's already in ISO format with Z, return as-is
+  if (dateString.endsWith('Z') || dateString.includes('+') || dateString.includes('T') && dateString.includes(':')) {
+    return dateString;
+  }
+  
+  // If it's a simple date string, force UTC interpretation
+  const date = new Date(dateString + 'Z');
   return date.toISOString();
 }
 
@@ -163,4 +169,4 @@ export const GET: APIRoute = async () => {
       },
     });
   }
-}; 
+};