feat(controlled): 实现设备激活与安全认证流程

- 添加API客户端、加密存储和provision/token激活逻辑
- WebSocket改用Bearer令牌认证，移除REGISTER请求
- 设备ID改为服务端下发，支持令牌刷新和强制下线处理
- 新增deviceSecret加密存储和accessToken自动刷新
- 更新设备ID获取方式为出厂SN，添加安全存储依赖

webrtc_controller_ios/web_rtc_controller_ios/WebRTC/WebRTCClient.swift

@@ -56,6 +56,9 @@ final class WebRTCClient: NSObject {
         super.init()
     }
 
+    /// 由服务端下发的 TURN 短期凭证覆盖默认 ICE 配置（为空时用内置 STUN/TURN）。
+    static var iceServersOverride: [[String: Any]]?
+
     var isDataChannelOpen: Bool {
         controlChannel?.readyState == .open
     }
@@ -71,13 +74,23 @@ final class WebRTCClient: NSObject {
         self.remoteRenderer = renderer
 
         let config = RTCConfiguration()
-        config.iceServers = [
-            RTCIceServer(urlStrings: ["stun:stun.l.google.com:19302"]),
-            RTCIceServer(urlStrings: ["stun:www.ttstd.com:3478"]),
-            RTCIceServer(urlStrings: ["turn:www.ttstd.com:3478"],
-                         username: "ttstd",
-                         credential: "ttstd123")
-        ]
+        if let override = WebRTCClient.iceServersOverride {
+            // 服务端下发的 TURN 短期凭证（RFC 7635）。
+            config.iceServers = override.compactMap { entry in
+                guard let urls = entry["urls"] as? String else { return nil }
+                return RTCIceServer(urlStrings: [urls],
+                                    username: entry["username"] as? String,
+                                    credential: entry["credential"] as? String)
+            }
+        } else {
+            config.iceServers = [
+                RTCIceServer(urlStrings: ["stun:stun.l.google.com:19302"]),
+                RTCIceServer(urlStrings: ["stun:www.ttstd.com:3478"]),
+                RTCIceServer(urlStrings: ["turn:www.ttstd.com:3478"],
+                             username: "ttstd",
+                             credential: "ttstd123")
+            ]
+        }
         config.sdpSemantics = .unifiedPlan
         config.continualGatheringPolicy = .gatherContinually
         config.iceCandidatePoolSize = 10