hero reel: remove walking shot, shorten opener

Drop v3-shot-03 (feet walking on carpet) from reel and trim v3-shot-02
opener from 4.5s to 3.0s. Bump cachebuster to v=7.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

index.html

@@ -19,7 +19,7 @@
 
     <section class="hero">
         <video class="hero-video" autoplay muted loop playsinline preload="auto">
-            <source src="/assets/videos/hero/hero-reel.mp4?v=6" type="video/mp4">
+            <source src="/assets/videos/hero/hero-reel.mp4?v=7" type="video/mp4">
         </video>
         <div class="hero-overlay"></div>