Add support page, admin features, and auth hardening.

Rename public affiliate route to /support with localized nav labels, and include affiliate/social/wallpaper admin, 2FA login, and related site updates.

Co-authored-by: Cursor <cursoragent@cursor.com>

Models/classes/sitesetting.cs

@@ -0,0 +1,17 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace atakanozbancom.Models.classes
+{
+    [Table("sitesettings")]
+    public class sitesetting
+    {
+        [Key]
+        public int id { get; set; }
+
+        // Public URL of the current wallpaper. Null/empty falls back to the bundled default.
+        [StringLength(500)]
+        [Column("wallpaper")]
+        public string wallpaper { get; set; }
+    }
+}