Change googleDriveAdapterHelper.js to use return statement

Reverted from object literal to function with return statement

Rationale:
- User requested explicit 'return' statement for clarity
- Function wrapper with 'return' is more conventional and readable
- Makes it clear the code returns an object when executed
- Matches common module pattern expectations

Structure:
```javascript
(function() {
  // Define all classes and functions
  class DocumentCountExceededError extends Error {...}
  function generateRequestId() {...}
  // ... all other functions

  // Return object with all exports
  return {
    DocumentCountExceededError,
    generateRequestId,
    // ... all other functions
  };
})();
```

Changes:
- Wrapped entire file in IIFE: (function() { ... })()
- Changed final expression from ({ ... }) to return { ... };
- Re-added 2-space indentation for content inside function
- Updated header comment: 'Returns' → 'Function that returns'

Benefits:
✅ Explicit return statement (clearer intent)
✅ Standard IIFE module pattern
✅ More conventional JavaScript style
✅ Easier to understand for new developers
✅ Same functionality as before

Testing:
✓ Syntax validated
✓ Server starts successfully
✓ Module loads: 'Loaded global functions: googleDriveAdapterHelper'
✓ All function calls work correctly
✓ Request handling functional

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/globalVariables/googleDriveAdapterHelper.js

@@ -6,7 +6,7 @@
  *
  * ARCHITECTURE:
  * - Loaded by server.js using vm.Script (same as proxy.js)
- * - Returns a single object containing all helper functions
+ * - Function that returns a single object containing all helper functions
  * - Injected into globalVariableContext for access by proxy.js
  * - NO IMPORTS - All dependencies provided via VM context
  *
@@ -17,6 +17,7 @@
  * @returns {Object} Helpers object with all utility functions
  */
 
+(function() {
   /**
    * Custom error for document count exceeding limit
    */
@@ -281,12 +282,11 @@ function parseRoute(method, url) {
   // All other paths return 404
   return { route: null, error: "Not found", statusCode: 404 };
   }
-
   // =============================================================================
   // Return helpers object with all functions
   // =============================================================================
 
-({
+  return {
   // Error classes
   DocumentCountExceededError,
   
@@ -309,4 +309,5 @@ generateSitemap,
   
   // Routing
   parseRoute,
-});
+  };
+})();