Fix admin route access and backend configuration

- Added /admin redirect to login page in nginx config
- Fixed backend server.js route ordering for proper admin handling
- Updated authentication middleware and routes
- Added user management routes
- Configured PostgreSQL integration
- Updated environment configuration

Models/SiteSettings.cs

@@ -0,0 +1,27 @@
+using System;
+using MongoDB.Bson;
+using MongoDB.Bson.Serialization.Attributes;
+
+namespace SkyArtShop.Models;
+
+[BsonIgnoreExtraElements]
+public class SiteSettings
+{
+	[BsonId]
+	[BsonRepresentation(BsonType.ObjectId)]
+	public string? Id { get; set; }
+
+	public string SiteName { get; set; } = "Sky Art Shop";
+
+	public string SiteTagline { get; set; } = "Scrapbooking and Journaling Fun";
+
+	public string ContactEmail { get; set; } = "info@skyartshop.com";
+
+	public string ContactPhone { get; set; } = "+501 608-0409";
+
+	public string InstagramUrl { get; set; } = "#";
+
+	public string FooterText { get; set; } = "© 2035 by Sky Art Shop. Powered and secured by Wix";
+
+	public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
+}