Fix lightbox overflow on Renegade and Nomad mobile

align-items: center clips content at both ends when taller than viewport.
Switch to align-items: flex-start + overflow-y: auto so gate scrolls from top.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Videos/renegade-storyteller.html

@@ -156,8 +156,9 @@
             background-color: rgba(4, 6, 11, 0.98);
             z-index: 1000;
             display: flex;
-            align-items: center;
+            align-items: flex-start;
             justify-content: center;
+            overflow-y: auto;
             padding: var(--space-6);
             opacity: 0;
             visibility: hidden;