Remove anon key from MarksAuth — open device registration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Marks/Services/MarksAuth.swift

@@ -1,9 +1,7 @@
 import Foundation
 import UIKit
 
-// Hardcoded backend config — no user-facing settings needed
-private let backendBaseURL = "https://magicive-api-production.up.railway.app"
-private let marksAnonKey  = "marks-anon-2025"
+private let backendBaseURL = "https://chatai-realtime-proxy-production.up.railway.app"
 
 private let tokenKey      = "marksJWT"
 private let tokenExpiryKey = "marksJWTExpiry"
@@ -34,7 +32,6 @@ enum MarksAuth {
         var req = URLRequest(url: url)
         req.httpMethod = "POST"
         req.setValue("application/json", forHTTPHeaderField: "Content-Type")
-        req.setValue(marksAnonKey, forHTTPHeaderField: "X-API-Key")
         req.httpBody = try JSONSerialization.data(withJSONObject: ["device_id": deviceId])
         let (data, response) = try await URLSession.shared.data(for: req)
         let status = (response as? HTTPURLResponse)?.statusCode ?? 0