fix(website): update hero video asset and changelog notes

Replace `public/zblade.mp4` with refreshed demo video
Center and constrain hero video container on the homepage
Update changelog with TTFT improvement and chat image resend bug fix

src/pages/changelog.astro

@@ -41,7 +41,7 @@ import BaseLayout from '../layouts/BaseLayout.astro';
                 Enhancements
               </h3>
               <ul class="changes-list">
-                <li><strong>Zaguán Coder Daemon.</strong> Tightened up the logic for Google Gemini 3.1 Pro.</li>
+                <li><strong>Zaguán Coder Daemon.</strong> Tightened up the logic for Google Gemini 3.1 Pro. TTFT now 4-5x faster.</li>
                 <li><strong>Git Panel.</strong> Enhanced Git Panel to show a strikethrough for elements that are moved, renamed or deleted.</li>
                 <li><strong>Chat.</strong> Added visual feedback while waiting for the model to respond in the chat.</li>
               </ul>
@@ -58,6 +58,7 @@ import BaseLayout from '../layouts/BaseLayout.astro';
                 <li><strong>Paste image.</strong> Fixed a bug where pasting images from clipboard into chat didn't work.</li>
                 <li><strong>Tab focus.</strong> Active tab now always stays in focus while new tabs are opening.</li>
                 <li><strong>Git.</strong> Fixed a bug where the <code>.zblade</code> directory would be submitted to git.</li>
+                <li><strong>Chat.</strong> Fixed a bug where images attached to a message were being re-sent on every subsequent turn, causing context bloat.</li>
               </ul>
             </div>
           </div>

src/pages/index.astro

@@ -43,9 +43,9 @@ const version = pkg.version ?? "";
       </div>
       
       <!-- Screenshot Reveal -->
-      <div class="container" style="margin-top: var(--space-2xl); position: relative; z-index: 2;">
+      <div class="container" style="margin-top: var(--space-2xl); position: relative; z-index: 2; display: flex; justify-content: center;">
-        <div style="border: 1px solid var(--color-border); border-radius: var(--border-radius); overflow: hidden; box-shadow: 0 20px 50px rgba(0,0,0,0.5), 0 0 30px rgba(0,221,119,0.1); background: var(--color-bg-elevated); padding: 2px;">
+        <div style="max-width: 420px; width: 100%; aspect-ratio: 16 / 9; border: 1px solid var(--color-border); border-radius: var(--border-radius); overflow: hidden; box-shadow: 0 20px 50px rgba(0,0,0,0.5), 0 0 30px rgba(0,221,119,0.1); background: var(--color-bg-elevated); padding: 2px;">
-          <video src="/zblade.mp4" autoplay loop muted playsinline preload="auto" style="width: 100%; height: auto; aspect-ratio: 16 / 9; object-fit: cover; object-position: center bottom; display: block; border-radius: var(--border-radius);">
+          <video src="/zblade.mp4" autoplay muted playsinline loop preload="auto" style="width: 100%; height: 100%; object-fit: cover; display: block; border-radius: var(--border-radius);">
             Your browser does not support the video tag.
           </video>
         </div>