fix: Global BigInt conversion in postgres module

- Added convertBigInt helper in db/postgres.ts
- Converts all BigInt values to Number in query results
- Simplified admin.ts routes (removed workarounds)
- All APIs now work correctly

src/db/postgres.ts

@@ -5,6 +5,22 @@ const DATABASE_URL = Deno.env.get("DATABASE_URL") ||
 
 let pool: Pool;
 
+// Convert BigInt to Number recursively in query results
+function convertBigInt<T>(obj: T): T {
+  if (obj === null || obj === undefined) return obj;
+  if (typeof obj === 'bigint') return Number(obj) as unknown as T;
+  if (obj instanceof Date) return obj;
+  if (Array.isArray(obj)) return obj.map(convertBigInt) as unknown as T;
+  if (typeof obj === 'object') {
+    const result: Record<string, unknown> = {};
+    for (const [key, value] of Object.entries(obj as Record<string, unknown>)) {
+      result[key] = convertBigInt(value);
+    }
+    return result as T;
+  }
+  return obj;
+}
+
 export async function initDB(): Promise<void> {
   pool = new Pool(DATABASE_URL, 10);
   
@@ -29,7 +45,8 @@ export async function query<T>(sql: string, params?: unknown[]): Promise<T[]> {
       text: sql,
       args: params || [],
     });
-    return result.rows;
+    // Convert BigInt to Number in all results
+    return result.rows.map(row => convertBigInt(row));
   } finally {
     client.release();
   }
@@ -47,7 +64,7 @@ export async function execute(sql: string, params?: unknown[]): Promise<number>
       text: sql,
       args: params || [],
     });
-    return result.rowCount || 0;
+    return Number(result.rowCount || 0);
   } finally {
     client.release();
   }