feat: responsive mobile UI across all pages

Global:
- Viewport meta already present; added -webkit-text-size-adjust: 100%
- Container padding reduces to 12px on mobile (was 24px)
- Smaller heading sizes (h1: 1.5rem, h2: 1.25rem)
- Buttons get min-height 40px for touch targets
- Inputs forced to 16px font-size to prevent iOS zoom
- Thinner scrollbar on mobile

Header:
- Logo text shrinks to 1rem on mobile, icon to 28px
- Header padding reduces to 12px

Library:
- Toolbar stacks vertically on mobile, full-width inputs
- Grid forced to 2 columns on narrow screens (480px), reduced gap

GameCard:
- Smaller info text, padding, badge on 480px screens

GameDetail:
- Cover section capped at 200px width on mobile
- Media thumbnails shrink to 160x90
- Scrape header stacks vertically with full-width buttons
- Edit rows stack vertically on mobile

Play:
- DOS container caps at 50vh on mobile, smaller border-radius
- Overlay text/icon sizes reduced, more compact layout

frontend/src/app.css

@@ -52,6 +52,7 @@
 html {
   font-size: 16px;
   -webkit-font-smoothing: antialiased;
+  -webkit-text-size-adjust: 100%;
 }
 
 body {
@@ -170,6 +171,19 @@ input::placeholder {
   margin: 0 auto;
   padding: 0 24px;
 }
+@media (max-width: 640px) {
+  .container { padding: 0 12px; }
+}
+
+/* ═══════════════════════════════════════════════════════════════
+   RESPONSIVE TOUCH ADJUSTMENTS
+   ═══════════════════════════════════════════════════════════════ */
+@media (max-width: 640px) {
+  h1 { font-size: 1.5rem; }
+  h2 { font-size: 1.25rem; }
+  .btn { padding: 8px 14px; font-size: 0.85rem; min-height: 40px; }
+  input, textarea, select { font-size: 16px; } /* prevents iOS zoom */
+}
 
 /* ═══════════════════════════════════════════════════════════════
    SCROLLBAR