Mobile viewport fixes: responsive card width, nav cleanup, season percentages

- Continue Watching card uses viewport-relative width on mobile (calc(100vw-3rem))
  with edge-to-edge scroll container using negative margin trick
- Nav bar hides user name on mobile (bottom tab bar shows it instead)
- Season rows show percentage text on mobile where progress bar is hidden
- Season 5 correctly shows "94%" instead of requiring the hidden progress bar

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

components/nav-bar.tsx

@@ -75,7 +75,7 @@ export function NavBar() {
                 <Kbd className="ml-1">⌘K</Kbd>
               </button>
               <div className="flex items-center gap-2 rounded-lg border border-border/30 px-2.5 py-1">
-                <span className="text-sm text-muted-foreground">
+                <span className="hidden text-sm text-muted-foreground sm:inline">
                   {session.user.name}
                 </span>
                 <button