fix(media-manager): resolve video preview issues and stabilize tests

- Backend (MediaService):
    - Implemented robust contentUrl generation for Drive files using drive.google.com/uc pattern.
    - Added mimeType exposure to unified media state.

- Frontend (MediaManager):
    - Replaced video tag with iframe embedding the Google Drive Preview player (/preview) for reliable playback.
    - Fixed syntax error in console logging causing UI freeze.
    - Updated gallery card logic to prioritize video content URLs.

- Tests (Integration):
    - Refactored mediaManager.integration.test.ts to align with new logic.
    - Mocked DriveApp completely to support orphan adoption flows.
    - Updated file renaming expectations to support timestamped filenames.

- Documentation:
    - Updated MEMORY.md with video preview strategy.

src/services/MediaService.ts

@@ -128,8 +128,12 @@ export class MediaService {
             source: match ? 'synced' : 'drive_only',
             thumbnail: `data:image/jpeg;base64,${Utilities.base64Encode(d.file.getThumbnail().getBytes())}`,
             status: 'active',
-            galleryOrder: d.galleryOrder
+            galleryOrder: d.galleryOrder,
+            mimeType: d.file.getMimeType(),
+            // Use manual download URL construction which is often more reliable for authenticated sessions than getDownloadUrl()
+            contentUrl: `https://drive.google.com/uc?export=download&id=${d.file.getId()}`
         })
+        // console.log(`[MediaService] File ${d.file.getName()} (${d.file.getId()}): Mime=${d.file.getMimeType()}, ContentUrl=https://drive.google.com/uc?export=download&id=${d.file.getId()}`)
     })
 
     // Find Shopify Orphans