Add touch swipe gestures + keyboard arrows to Crate Digger

frontend/src/pages/CrateDigger.tsx

@@ -1,4 +1,4 @@
-import { useState, useCallback, useEffect } from 'react'
+import { useState, useCallback, useEffect, useRef } from 'react'
 import { Disc3, X, Heart, ExternalLink, Loader2, RotateCcw } from 'lucide-react'
 import { fillCrate, crateSave, type CrateItem } from '../lib/api'
 
@@ -80,6 +80,52 @@ export default function CrateDigger() {
     advanceCard()
   }, [cardState, crate, currentIndex, advanceCard])
 
+  // Touch swipe handling
+  const touchStartX = useRef<number | null>(null)
+  const touchStartY = useRef<number | null>(null)
+  const [swipeOffset, setSwipeOffset] = useState(0)
+  const cardRef = useRef<HTMLDivElement>(null)
+
+  const handleTouchStart = useCallback((e: React.TouchEvent) => {
+    touchStartX.current = e.touches[0].clientX
+    touchStartY.current = e.touches[0].clientY
+  }, [])
+
+  const handleTouchMove = useCallback((e: React.TouchEvent) => {
+    if (touchStartX.current === null || cardState !== 'visible') return
+    const dx = e.touches[0].clientX - touchStartX.current
+    const dy = e.touches[0].clientY - (touchStartY.current || 0)
+    // Only swipe horizontally if horizontal movement > vertical
+    if (Math.abs(dx) > Math.abs(dy)) {
+      e.preventDefault()
+      setSwipeOffset(dx)
+    }
+  }, [cardState])
+
+  const handleTouchEnd = useCallback(() => {
+    if (touchStartX.current === null) return
+    const threshold = 80
+    if (swipeOffset > threshold) {
+      handleSave()
+    } else if (swipeOffset < -threshold) {
+      handlePass()
+    }
+    setSwipeOffset(0)
+    touchStartX.current = null
+    touchStartY.current = null
+  }, [swipeOffset, handleSave, handlePass])
+
+  // Keyboard support
+  useEffect(() => {
+    const handleKey = (e: KeyboardEvent) => {
+      if (cardState !== 'visible' || finished || crate.length === 0) return
+      if (e.key === 'ArrowLeft') handlePass()
+      if (e.key === 'ArrowRight') handleSave()
+    }
+    window.addEventListener('keydown', handleKey)
+    return () => window.removeEventListener('keydown', handleKey)
+  }, [cardState, finished, crate.length, handlePass, handleSave])
+
   const currentItem = crate[currentIndex]
 
   // Empty state — no crate loaded yet
@@ -194,13 +240,23 @@ export default function CrateDigger() {
       {/* Card */}
       {currentItem && (
         <div
-          className={`bg-white rounded-2xl shadow-lg border border-purple-100 overflow-hidden transition-all duration-300 ${
+          ref={cardRef}
+          onTouchStart={handleTouchStart}
+          onTouchMove={handleTouchMove}
+          onTouchEnd={handleTouchEnd}
+          className={`bg-white rounded-2xl shadow-lg border border-purple-100 overflow-hidden select-none ${
             cardState === 'saving'
-              ? 'opacity-0 translate-x-24'
+              ? 'transition-all duration-300 opacity-0 translate-x-48 rotate-6'
               : cardState === 'passing'
-                ? 'opacity-0 -translate-x-24'
-                : 'opacity-100 translate-x-0'
+                ? 'transition-all duration-300 opacity-0 -translate-x-48 -rotate-6'
+                : swipeOffset === 0
+                  ? 'transition-all duration-300 opacity-100 translate-x-0 rotate-0'
+                  : ''
           }`}
+          style={swipeOffset !== 0 ? {
+            transform: `translateX(${swipeOffset}px) rotate(${swipeOffset * 0.05}deg)`,
+            opacity: Math.max(0.3, 1 - Math.abs(swipeOffset) / 300),
+          } : undefined}
         >
           {/* Album art placeholder */}
           <div className="h-48 bg-gradient-to-br from-purple-600 via-purple-500 to-purple-800 flex items-center justify-center relative">
@@ -239,6 +295,18 @@ export default function CrateDigger() {
         </div>
       )}
 
+      {/* Swipe indicators */}
+      {swipeOffset !== 0 && (
+        <div className="flex justify-between px-4 mt-3">
+          <span className={`text-sm font-bold transition-opacity ${swipeOffset < -40 ? 'opacity-100 text-red-500' : 'opacity-0'}`}>
+            ← PASS
+          </span>
+          <span className={`text-sm font-bold transition-opacity ${swipeOffset > 40 ? 'opacity-100 text-green-500' : 'opacity-0'}`}>
+            SAVE →
+          </span>
+        </div>
+      )}
+
       {/* Action buttons */}
       <div className="flex items-center justify-center gap-8 mt-8">
         <button
@@ -261,7 +329,7 @@ export default function CrateDigger() {
 
       {/* Keyboard hints */}
       <p className="text-center text-charcoal-muted text-xs mt-4">
-        Tap the buttons to pass or save
+        Swipe or use buttons · Arrow keys on desktop
       </p>
     </div>
   )