perf(booth): optimize assets and result flow

WebP reduces UI payload; JPEG keeps portrait saves compatible.\nFinish ends the visit without prompting another portrait.

app/globals.css

@@ -171,6 +171,24 @@ body {
     border-width: 0 !important;
     box-shadow: none !important;
   }
+
+  /* Tailwind's 12px text-xs was too small for the touch-first booth screens. */
+  .kiosk-viewport .text-xs {
+    font-size: 0.875rem;
+    line-height: 1.25rem;
+  }
+
+  .kiosk-viewport [class~="text-[10px]"],
+  .kiosk-viewport [class~="text-[11px]"],
+  .kiosk-viewport [class~="text-[12px]"] {
+    font-size: 0.875rem;
+    line-height: 1.25rem;
+  }
+
+  .kiosk-viewport .kiosk-footer-label {
+    font-size: 0.625rem !important;
+    line-height: 0.875rem !important;
+  }
 }
 
 /* Fullscreen Mode URL parameter reset (?mode=fullscreen) */