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.

MEMORY.md

@@ -40,5 +40,9 @@ This project (`product_inventory`) integrates Google Sheets with Shopify. It ser
         1. Sanitize with `Utilities.newBlob()`.
         2. Fallback to **Advanced Drive Service** (`Drive.Files.create` / `v3`) if standard creation fails.
 - **Video Previews**:
-    - HTML5 `<video>` tags often fail with standard Drive download URLs due to auth/codec issues.
-    - **Strategy**: Use an `<iframe>` embedding the `https://drive.google.com/file/d/{ID}/preview` URL. This leverages Google's native player for reliable auth and transcoding.
+- **Video Previews**:
+    - Use `document.createElement('video')` to inject video tags. Avoid template strings (`<video src="...">`) as the parser sanitizes them aggressively.
+    - Fallback to `<iframe>` only if native playback fails.
+- **Client-Side Syntax**:
+    - **ES5 ONLY**: Do not use `class` in client-side HTML files. The Apps Script sanitizer often fails to parse them. Use `function` constructors.
+

docs/ARCHITECTURE.md

@@ -141,3 +141,19 @@ We implemented a "Sidebar-First" architecture for product media to handle the co
     - Calculates checksums to avoid re-uploading duplicate images.
     - Uses Shopify's "Staged Uploads" -> "Create Media" mutation flow.
 
+### 8. Apps Script & HTML Service Constraints
+
+When working with `HtmlService` (client-side code), the environment differs significantly from the server-side V8 runtime.
+
+1.  **Server-Side (`.ts`/`.gs`)**:
+    -   **Runtime**: V8 Engine.
+    -   **Syntax**: Modern ES6+ (Classes, Arrow Functions, `const`/`let`) is fully supported.
+    -   **Recommendation**: Use standard TypeScript patterns.
+
+2.  **Client-Side (`.html` served via `createHtmlOutputFromFile`)**:
+    -   **Runtime**: Legacy Browser Environment / Strict Caja Sanitization.
+    -   **Constraint**: The parser often chokes on ES6 `class` syntax and complex template strings inside HTML attributes.
+    -   **Rule 1**: **NO ES6 CLASSES**. Use ES5 `function` constructors and `prototype` methods.
+    -   **Rule 2**: **NO Complex Template Strings in Attributes**. Do not use `src="${var}"` if the variable contains a URL. Use `document.createElement` and set properties (e.g., `element.src = value`) programmatically.
+    -   **Rule 3**: **Unified Script Tags**. Consolidate scripts into a single block where possible to avoid parser merge errors.
+    -   **Rule 4**: **Var over Let/Const**. Top-level variables should use `var` or explicit `window` assignment to ensure they are accessible to inline HTML handlers (e.g., `onclick="handler()"`).

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) {

src/services/MediaService.ts

@@ -139,6 +139,20 @@ export class MediaService {
     // Find Shopify Orphans
     shopifyMedia.forEach(m => {
         if (!matchedShopifyIds.has(m.id)) {
+            let mimeType = 'image/jpeg'; // Default
+            let contentUrl = "";
+
+            if (m.mediaContentType === 'VIDEO' && m.sources) {
+                // Find MP4
+                const mp4 = m.sources.find((s: any) => s.mimeType === 'video/mp4')
+                if (mp4) {
+                    mimeType = mp4.mimeType
+                    contentUrl = mp4.url
+                }
+            } else if (m.mediaContentType === 'IMAGE' && m.image) {
+                contentUrl = m.image.url
+            }
+
             unifiedState.push({
                 id: m.id, // Use Shopify ID keys for orphans
                 driveId: null,
@@ -148,7 +162,9 @@ export class MediaService {
                 source: 'shopify_only',
                 thumbnail: m.preview?.image?.originalSrc || "",
                 status: 'active',
-                galleryOrder: 10000 // End of list
+                galleryOrder: 10000, // End of list
+                mimeType: mimeType,
+                contentUrl: contentUrl
             })
         }
     })

src/services/ShopifyMediaService.ts

@@ -78,6 +78,17 @@ export class ShopifyMediaService implements IShopifyMediaService {
                     originalSrc
                   }
                 }
+                ... on Video {
+                  sources {
+                    url
+                    mimeType
+                  }
+                }
+                ... on MediaImage {
+                  image {
+                    url
+                  }
+                }
               }
             }
           }