fix(app): iOS HIG Phase 5 — glass button system & .touch-target utility

- Add responsive glass-button-sm: 44px min-height on mobile (≤768px)
- Replace !h-7 !min-h-0 overrides with responsive min-h-[44px] md:min-h-0
- Add .touch-target utility class (44px min, inline-flex centered)
- Refactor 21 icon buttons to use .touch-target class

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

packages/app/src/styles/main.css

@@ -126,6 +126,24 @@ body {
     padding-inline: 0.75rem;
   }
 
+  .touch-target {
+    min-width: 44px;
+    min-height: 44px;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+  }
+
+  @media (max-width: 768px) {
+    .glass-button {
+      min-height: 48px;
+    }
+
+    .glass-button-sm {
+      min-height: 44px !important;
+    }
+  }
+
   .gradient-card {
     background: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(0, 0, 0, 0.8) 100%);
     backdrop-filter: blur(18px);