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

Controllers/ContactController.cs

@@ -0,0 +1,29 @@
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using SkyArtShop.Models;
+using SkyArtShop.Services;
+
+namespace SkyArtShop.Controllers;
+
+public class ContactController : Controller
+{
+	private readonly PostgreSQLService _pgService;
+
+	public ContactController(PostgreSQLService pgService)
+	{
+		_pgService = pgService;
+	}
+
+	public async Task<IActionResult> Index()
+	{
+		SiteSettings model = (await _pgService.GetSiteSettingsAsync()) ?? new SiteSettings();
+		return View(model);
+	}
+
+	[HttpPost]
+	public IActionResult Submit(string name, string email, string phone, string subject, string message)
+	{
+		base.TempData["Success"] = "Thank you! Your message has been sent. We'll get back to you soon.";
+		return RedirectToAction("Index");
+	}
+}