Skip videos without playback URL

Videos without a playback_url are now filtered out in all contexts:
- Realtime event notifications
- Scheduled assets (per_album/random mode)
- Scheduled assets (combined mode)

This prevents sending video entries that cannot be played back.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

manifest.json

@@ -1,3 +1,3 @@
 {
-  "version": "1.22.6"
+  "version": "1.22.7"
 }