125x125 sidebar banner (sized ad serving) + shorts report link

- New 125x125 "square button" banner size; ad serve now filters by width/height,
  and the sidebar slot serves a 125x125 banner (empty until such inventory exists).
- Shorts reel gets a "report this short" link (posts to /api/report-ad).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/assets/my.js

@@ -1714,7 +1714,7 @@
   // banner + text placements inside the back office (they ARE the audience)
   IAP.adSlot('banner', 'adSlotLogin');
   IAP.adSlot('banner', 'adSlotOverview');
-  IAP.adSlot('text', 'adSlotSide');
+  IAP.adSlot('banner', 'adSlotSide', { width: 125, height: 125 }); // square button ad in the sidebar
 
   render();
 })();