fix: 修复 pairing required - 改用 openclaw-control-ui 客户端 ID 触发静默自动配对

上游源码分析发现根本原因：
- Gateway 的 shouldAllowSilentLocalPairing 需要 isControlUi=true
  才能在本地连接时静默自动批准设备配对
- 我们之前用 gateway-client+backend，isControlUi=false，加上
  Tauri WebView 会发 Origin 头（hasBrowserOriginHeader=true），
  导致 shouldAllowSilentLocalPairing 返回 false → 'pairing required'

修复内容：
- device.rs: client.id 改为 openclaw-control-ui，mode 改为 ui，
  v3 签名 payload 同步更新，本地连接触发静默自动配对
- pairing.rs: paired.json 的 clientId/clientMode 同步更新
- main.js: 启动时自动调用 autoPairDevice()，确保 device 已配对
  + allowedOrigins 已写入，无需用户手动点击一键修复

src-tauri/src/commands/device.rs

@@ -101,8 +101,10 @@ pub fn create_connect_frame(nonce: String, gateway_token: String) -> Result<Valu
 
     let scopes_str = SCOPES.join(",");
     // v3 格式：v3|deviceId|clientId|clientMode|role|scopes|signedAt|token|nonce|platform|deviceFamily
+    // 使用 openclaw-control-ui + ui 模式，使 Gateway 识别为 Control UI 客户端，
+    // 本地连接时触发静默自动配对（shouldAllowSilentLocalPairing = true）
     let payload_str = format!(
-        "v3|{device_id}|gateway-client|backend|operator|{scopes_str}|{signed_at}|{gateway_token}|{nonce}|{platform}|{device_family}"
+        "v3|{device_id}|openclaw-control-ui|ui|operator|{scopes_str}|{signed_at}|{gateway_token}|{nonce}|{platform}|{device_family}"
     );
 
     let signature = signing_key.sign(payload_str.as_bytes());
@@ -116,11 +118,11 @@ pub fn create_connect_frame(nonce: String, gateway_token: String) -> Result<Valu
             "minProtocol": 3,
             "maxProtocol": 3,
             "client": {
-                "id": "gateway-client",
+                "id": "openclaw-control-ui",
                 "version": "1.0.0",
                 "platform": platform,
                 "deviceFamily": device_family,
-                "mode": "backend"
+                "mode": "ui"
             },
             "role": "operator",
             "scopes": SCOPES,

src-tauri/src/commands/pairing.rs

@@ -62,8 +62,8 @@ pub fn auto_pair_device() -> Result<String, String> {
         "deviceId": device_id,
         "publicKey": public_key,
         "platform": "desktop",
-        "clientId": "gateway-client",
-        "clientMode": "backend",
+        "clientId": "openclaw-control-ui",
+        "clientMode": "ui",
         "role": "operator",
         "roles": ["operator"],
         "scopes": [