feat(api): implement product caching mechanism

- Add NODE_ENV=production to .env for environment configuration
- Enhance product API route with JSON cache manager for local storage and retrieval
- Introduce cache-only mode and detailed logging for better performance and offline support
- Update UI to display cache status and storage statistics

hooks/useCacheOnlyMode.ts

@@ -0,0 +1,30 @@
+"use client";
+
+import { useState, useEffect } from "react";
+
+export function useCacheOnlyMode() {
+  const [cacheOnly, setCacheOnly] = useState(false);
+  const isProd = process.env.NODE_ENV === "production";
+
+  useEffect(() => {
+    if (isProd) {
+      const saved = localStorage.getItem("cache_only_mode");
+      setCacheOnly(saved === "true");
+    }
+  }, [isProd]);
+
+  useEffect(() => {
+    const handleStorageChange = () => {
+      const saved = localStorage.getItem("cache_only_mode");
+      setCacheOnly(saved === "true");
+    };
+
+    window.addEventListener("storage", handleStorageChange);
+    return () => window.removeEventListener("storage", handleStorageChange);
+  }, []);
+
+  return {
+    cacheOnly: isProd ? cacheOnly : false,
+    isProd,
+  };
+}