Fix Media Manager critical syntax errors and enforce ES5 architecture

- Resolved persistent 'SyntaxError: Unexpected token class' by refactoring 'MediaState' and 'UI' classes in MediaManager.html to standard ES5 function constructors.

- Resolved 'SyntaxError: Unexpected identifier src' by rewriting 'createCard' to use 'document.createElement' instead of template strings for dynamic media elements.

- Consolidated script tags in MediaManager.html to prevent Apps Script parser merge issues.

- Updated docs/ARCHITECTURE.md and MEMORY.md to formally document client-side constraints (No ES6 classes, strict DOM manipulation for media).

- Note: Google Drive video animate-on-hover functionality is implemented but currently pending verification/fix.

src/mediaHandlers.ts

@@ -107,7 +107,13 @@ export function getMediaDiagnostics(sku: string) {
 
   const shopifyId = product.shopify_id || ""
 
-  return mediaService.getDiagnostics(sku, shopifyId)
+  const diagnostics = mediaService.getDiagnostics(sku, shopifyId)
+
+  // Inject OAuth token for frontend video streaming (Drive API alt=media)
+  return {
+    ...diagnostics,
+    token: ScriptApp.getOAuthToken()
+  }
 }
 
 export function saveFileToDrive(sku: string, filename: string, mimeType: string, base64Data: string) {