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/shorts.html

@@ -4,7 +4,7 @@
 <meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1">
 <title>Shorts | InstantAdPay</title>
 <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Sora:wght@600;700;800&display=swap">
-<link rel="stylesheet" href="/assets/site.css?v=20260907s">
+<link rel="stylesheet" href="/assets/site.css?v=20260907v">
 <style>
   html,body{height:100%;margin:0;overflow:hidden;background:#000}
   .sh{position:fixed;inset:0;display:flex;flex-direction:column;background:#000;color:var(--ink,#e8fff7)}
@@ -40,9 +40,10 @@
         <a class="btn small" id="shCta" target="_blank" rel="noopener nofollow" hidden>Learn more</a>
         <button class="btn small sec" id="shNext" type="button" hidden>Next short →</button>
       </div>
+      <a href="#" id="shReport" class="sh-report">⚠ report this short</a>
     </div>
   </div>
 </div>
-<script src="/assets/shorts.js?v=20260907e"></script>
+<script src="/assets/shorts.js?v=20260907v"></script>
 </body>
 </html>