perf(booth): optimize assets and result flow

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

components/screens/StyleScreen.tsx

@@ -37,7 +37,7 @@ export const StyleScreen: React.FC<StyleScreenProps> = ({
       <div className="w-full flex items-center justify-between px-1 mb-1 z-30 min-h-[40px]">
         <button
           onClick={onBack}
-          className="p-2 px-3 game-btn-dark flex items-center space-x-1 font-bold text-xs shrink-0 cursor-pointer shadow-md"
+          className="p-2 px-3 game-btn-dark flex items-center space-x-1 font-bold text-sm shrink-0 cursor-pointer shadow-md"
           title="Back"
         >
           <ArrowLeft size={16} className="stroke-[2.5]" />
@@ -47,7 +47,7 @@ export const StyleScreen: React.FC<StyleScreenProps> = ({
         {/* Top-Right Confirm / Transform Button - Clean text, no icon */}
         <button
           onClick={handleConfirm}
-          className="py-2 px-3.5 game-btn-gold font-extrabold text-xs tracking-wider flex items-center justify-center uppercase font-cinzel shadow-lg active:scale-95 cursor-pointer"
+          className="py-2 px-3.5 game-btn-gold font-extrabold text-sm tracking-wider flex items-center justify-center uppercase font-cinzel shadow-lg active:scale-95 cursor-pointer"
         >
           <span>{t(config.labels.confirmStyleButton)}</span>
         </button>
@@ -88,7 +88,7 @@ export const StyleScreen: React.FC<StyleScreenProps> = ({
 
               {/* Title & Tag */}
               <div className="mt-2 text-center w-full px-1">
-                <span className="block text-xs font-bold text-amber-100 truncate drop-shadow-[0_1px_2px_rgba(0,0,0,0.9)]">
+                <span className="block text-sm font-bold text-amber-100 truncate drop-shadow-[0_1px_2px_rgba(0,0,0,0.9)]">
                   {styleName}
                 </span>
               </div>