Align Copilot callout width

Constrain the homepage Copilot callout to the same 748px content measure as the pattern comparison above it.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 59dbd278-4a95-4fc4-8ec9-e238479eb5e4

Author: brunoborges

site/styles.css

@@ -2107,12 +2107,12 @@ footer a:hover {
   display: flex;
   align-items: center;
   gap: 16px;
+  max-width: 748px;
   background: var(--surface);
   border: 1px solid var(--accent);
   border-radius: 12px;
   padding: 16px 24px;
-  margin-top: 16px;
-  margin-bottom: 8px;
+  margin: 16px auto 8px;
 }
 .copilot-icon {
   width: 36px;