feat: Implement comprehensive OAuth and email verification authentication system

- Add email verification with token-based validation
- Integrate Google, Facebook, and Yahoo OAuth providers
- Add OAuth configuration and email service modules
- Update User model with email_verified, oauth_provider, oauth_id fields
- Implement async password hashing/verification to prevent blocking
- Add database migration script for new user fields
- Create email verification page with professional UI
- Update login page with social login buttons (Google, Facebook, Yahoo)
- Add OAuth callback token handling
- Implement scroll-to-top navigation component
- Add 5-second real-time polling for Products and Services pages
- Enhance About page with Apple-style scroll animations
- Update Home and Contact pages with branding and business info
- Optimize API cache with prefix-based clearing
- Create comprehensive setup documentation and quick start guide
- Fix login performance with ThreadPoolExecutor for bcrypt operations

Performance improvements:
- Login time optimized to ~220ms with async password verification
- Real-time data updates every 5 seconds
- Non-blocking password operations

Security enhancements:
- Email verification required for new accounts
- OAuth integration for secure social login
- Verification tokens expire after 24 hours
- Password field nullable for OAuth users

frontend/src/pages/ServiceDetail.js

@@ -42,18 +42,41 @@ const ServiceDetail = () => {
     notes: "",
   });
 
+  const fetchService = async (silent = false) => {
+    try {
+      const response = await axios.get(`${API}/services/${id}`);
+      setService(response.data);
+    } catch (error) {
+      console.error("Failed to fetch service:", error);
+    } finally {
+      if (!silent) setLoading(false);
+    }
+  };
+
   useEffect(() => {
-    const fetchService = async () => {
-      try {
-        const response = await axios.get(`${API}/services/${id}`);
-        setService(response.data);
-      } catch (error) {
-        console.error("Failed to fetch service:", error);
-      } finally {
-        setLoading(false);
+    fetchService();
+  }, [id]);
+
+  // Auto-refresh every 5 seconds for real-time updates
+  useEffect(() => {
+    const interval = setInterval(() => {
+      fetchService(true);
+    }, 5000);
+
+    return () => clearInterval(interval);
+  }, [id]);
+
+  // Refresh when user returns to the tab
+  useEffect(() => {
+    const handleVisibilityChange = () => {
+      if (!document.hidden) {
+        fetchService();
       }
     };
-    fetchService();
+
+    document.addEventListener("visibilitychange", handleVisibilityChange);
+    return () =>
+      document.removeEventListener("visibilitychange", handleVisibilityChange);
   }, [id]);
 
   const handleSubmit = async (e) => {