Implement literal function body pattern for global variable functions

Changed architecture so .js files contain literal function bodies

Changes to googleDriveAdapterHelper.js:
1. Changed from object literal (\({...}\)) to return statement (return {...})
2. File now contains LITERAL BODY of a function
3. Updated header comment to explain this pattern
4. File is NO LONGER valid standalone JavaScript (has bare return)

Changes to server.js loadGlobalVariables():
1. Wrap loaded code in function: `(function() { ${code} })()`
2. Creates IIFE that executes the function body
3. Captures returned object from the function
4. Pattern applies to ALL .js files in globalVariables/

Pattern:
```javascript
// File: googleDriveAdapterHelper.js (literal function body)
class DocumentCountExceededError extends Error {...}
function generateRequestId() {...}

return {
  DocumentCountExceededError,
  generateRequestId,
  // ... all exports
};
```

```javascript
// server.js wraps it:
const wrappedCode = `(function() {
${code}
})()`;
const script = new vm.Script(wrappedCode, { filename: file });
const returnedObject = script.runInContext(context);
```

Benefits:
✅ Files represent pure function bodies
✅ Wrapping logic centralized in server.js
✅ Clear separation: content vs. execution wrapper
✅ Explicit return statement in function body
✅ Consistent pattern for all global variable functions
✅ Easy to understand: file = function body, server = wrapper

Testing:
✓ Server starts successfully
✓ Module loads: 'Loaded global functions: googleDriveAdapterHelper'
✓ Object captured: type=object, keys=11
✓ All functions accessible in VM context
✓ proxy.js can call googleDriveAdapterHelper.* functions

Note: googleDriveAdapterHelper.js will show syntax error if run standalone
(has bare return statement) - this is intentional, it's a function body!

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

src/globalVariables/googleDriveAdapterHelper.js

@@ -5,8 +5,9 @@
  * to improve code organization while maintaining vm.Script isolation pattern.
  *
  * ARCHITECTURE:
- * - Loaded by server.js using vm.Script (same as proxy.js)
- * - Returns a single object containing all helper functions
+ * - This file contains the LITERAL BODY of a function
+ * - server.js wraps this in a function: (function() { <this code> })()
+ * - Function returns a single object containing all helper functions
  * - Injected into globalVariableContext for access by proxy.js
  * - NO IMPORTS - All dependencies provided via VM context
  *
@@ -286,27 +287,27 @@ return { route: null, error: "Not found", statusCode: 404 };
 // Return helpers object with all functions
 // =============================================================================
 
-({
-// Error classes
-DocumentCountExceededError,
+return {
+  // Error classes
+  DocumentCountExceededError,
 
-// Utilities
-generateRequestId,
-validateDocumentId,
-validateDocumentCount,
+  // Utilities
+  generateRequestId,
+  validateDocumentId,
+  validateDocumentCount,
 
-// XML
-escapeXml,
+  // XML
+  escapeXml,
 
-// Error mapping
-mapDriveErrorToHttp,
+  // Error mapping
+  mapDriveErrorToHttp,
 
-// Sitemap
-toSitemapEntry,
-transformDocumentsToSitemapEntries,
-generateSitemapXML,
-generateSitemap,
+  // Sitemap
+  toSitemapEntry,
+  transformDocumentsToSitemapEntries,
+  generateSitemapXML,
+  generateSitemap,
 
-// Routing
-parseRoute,
-});
+  // Routing
+  parseRoute,
+};

src/server.js

@@ -54,7 +54,10 @@ function loadGlobalVariables() {
   jsFiles.forEach((file) => {
     const varName = file.replace(".js", "");
     const code = readFileSync(join(globalDir, file), "utf-8");
-    const script = new vm.Script(code, { filename: file });
+    
+    // Wrap the literal function body in a function and execute
+    const wrappedCode = `(function() {\n${code}\n})()`;
+    const script = new vm.Script(wrappedCode, { filename: file });
     const context = vm.createContext({ ...globalVMContext, ...globalVariableContext });
     
     // Execute script and capture returned object