🔧 Fix asset file references for Portal presentation render

- Update DashboardOverviewScene to use einundzwanzig-square-inverted.svg
  instead of non-existent einundzwanzig-logo.png
- Fix MeetupShowcaseScene logo extensions: EinundzwanzigKempten.jpg and
  EinundzwanzigMemmingen.jpg (were incorrectly .png)
- Fix TopMeetupsScene logo extensions: EinundzwanzigKempten.jpg and
  EinundzwanzigTrier.jpg (were incorrectly .png)
- Update corresponding mobile scenes with same fixes
- Update test file expectations to match corrected extensions

These fixes enable successful full render of both PortalPresentation
(1920x1080) and PortalPresentationMobile (1080x1920) compositions.

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

videos/src/scenes/portal/mobile/TopMeetupsSceneMobile.tsx

@@ -38,7 +38,7 @@ const TOP_MEETUPS_DATA = [
   },
   {
     name: "EINUNDZWANZIG Kempten",
-    logoFile: "EinundzwanzigKempten.png",
+    logoFile: "EinundzwanzigKempten.jpg",
     userCount: 20,
     location: "Kempten",
     sparklineData: [3, 5, 7, 9, 11, 13, 15, 16, 17, 18, 19, 20],
@@ -54,7 +54,7 @@ const TOP_MEETUPS_DATA = [
   },
   {
     name: "EINUNDZWANZIG Trier",
-    logoFile: "EinundzwanzigTrier.png",
+    logoFile: "EinundzwanzigTrier.jpg",
     userCount: 15,
     location: "Trier",
     sparklineData: [2, 3, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15],