feat(shopping): hook useWakeLock avec fallback gracieux

frontend/src/hooks/useWakeLock.ts

@@ -0,0 +1,26 @@
+import { useEffect, useRef } from 'react'
+
+export function useWakeLock(active: boolean) {
+  const lockRef = useRef<WakeLockSentinel | null>(null)
+
+  useEffect(() => {
+    if (!active) {
+      lockRef.current?.release().catch(() => {})
+      lockRef.current = null
+      return
+    }
+
+    if (!('wakeLock' in navigator)) return
+
+    navigator.wakeLock.request('screen').then(lock => {
+      lockRef.current = lock
+    }).catch(() => {
+      // Wake Lock non disponible (mode économie d'énergie, navigateur non supporté)
+    })
+
+    return () => {
+      lockRef.current?.release().catch(() => {})
+      lockRef.current = null
+    }
+  }, [active])
+}