feat: Add custom video thumbnails for Drive uploads

- Implemented custom thumbnail injection in GASDriveService.getResumableUploadUrl.
- Fetches thumbnails from Google Photos using w320 size to avoid API limits.
- Added strict < 2MB size check for thumbnails.
- Updated mediaHandlers and MediaManager to pass sourceUrl to the backend.
- This allows Drive to display a visual cue immediately for video files still processing.

src/MediaManager.html

@@ -1364,7 +1364,7 @@
 
                       })
                     .withFailureHandler(e => ui.logStatus('error', `Ticket failed: ${e.message}`, 'error'))
-                    .getUploadUrl(state.sku, filename, mimeType);
+                    .getUploadUrl(state.sku, filename, mimeType, fetchUrl);
                 })
                 .withFailureHandler(e => {
                   ui.logStatus('error', `Cannot transfer ${filename}: ${e.message}`, 'error');

src/mediaHandlers.ts

@@ -128,7 +128,7 @@ export function linkDriveFileToShopifyMedia(sku: string, driveId: string, shopif
 }
 
 // NEW: Resumable Upload Ticket
-export function getUploadUrl(sku: string, filename: string, mimeType: string) {
+export function getUploadUrl(sku: string, filename: string, mimeType: string, sourceUrl?: string) {
   const config = new Config()
   const driveService = new GASDriveService()
 
@@ -136,7 +136,7 @@ export function getUploadUrl(sku: string, filename: string, mimeType: string) {
   const folder = driveService.getOrCreateFolder(sku, config.productPhotosFolderId)
 
   // Generate Ticket
-  return driveService.getResumableUploadUrl(filename, mimeType, folder.getId())
+  return driveService.getResumableUploadUrl(filename, mimeType, folder.getId(), sourceUrl)
 }
 
 // Deprecated (but kept for fallback/legacy small files if needed)

src/services/GASDriveService.ts

@@ -100,16 +100,59 @@ export class GASDriveService implements IDriveService {
     }
   }
 
-  getResumableUploadUrl(filename: string, mimeType: string, folderId: string): string {
+  getResumableUploadUrl(filename: string, mimeType: string, folderId: string, sourceUrl?: string): string {
     const token = ScriptApp.getOAuthToken();
 
     // Metadata for the file to be created
-    const metadata = {
+    const metadata: any = {
       name: filename,
       mimeType: mimeType,
       parents: [folderId]
     };
 
+    // feature: video-thumbnails-for-processing
+    // If this is a video from Google Photos, fetch a thumbnail and set as contentHint.
+    if (sourceUrl && sourceUrl.includes('googleusercontent.com') && mimeType.startsWith('video/')) {
+        try {
+            console.log(`[GASDriveService] Fetching thumbnail for ${filename}...`);
+            // =w800-h600 gives a decent sized jpeg thumbnail
+            // Use same auth token as we use for the video fetch
+            let thumbUrl = sourceUrl;
+            if (!thumbUrl.includes('=')) {
+                thumbUrl += '=w320-h320';
+            } else {
+                 thumbUrl = thumbUrl.replace(/=.*$/, '') + '=w320-h320';
+            }
+
+            const thumbResp = UrlFetchApp.fetch(thumbUrl, {
+                headers: { Authorization: `Bearer ${token}` },
+                muteHttpExceptions: true
+            });
+
+            if (thumbResp.getResponseCode() === 200) {
+                const thumbBlob = thumbResp.getBlob();
+                const base64Thumb = Utilities.base64EncodeWebSafe(thumbBlob.getBytes());
+
+                // Drive API Limit check (2MB)
+                if (base64Thumb.length < 2 * 1024 * 1024) {
+                    metadata.contentHints = {
+                        thumbnail: {
+                            image: base64Thumb,
+                            mimeType: 'image/jpeg'
+                        }
+                    };
+                    console.log(`[GASDriveService] Custom thumbnail injected (${base64Thumb.length} chars).`);
+                } else {
+                   console.warn(`[GASDriveService] Thumbnail too large (${base64Thumb.length} chars). Skipping injection.`);
+                }
+            } else {
+                console.warn(`[GASDriveService] Thumbnail fetch failed: ${thumbResp.getResponseCode()}`);
+            }
+        } catch (e) {
+            console.warn(`[GASDriveService] Thumbnail generation failed: ${e.message}`);
+        }
+    }
+
     const params = {
       method: 'post' as const,
       contentType: 'application/json',