feat!: 移除内置公共服务器

- 移除公共 RustDesk ID 服务器 (用户需自行配置)
- 移除公共 TURN 服务器 (仅保留 Google STUN)
- 清理废弃代码: PublicServerInfo, is_using_public_server 等
- 更新前端 UI 和国际化文本
- 重新生成 TypeScript 类型

破坏性变更: 不再提供内置公共服务器。用户必须配置自己的
RustDesk 服务器和 TURN 服务器才能在生产环境中使用。

web/src/i18n/en-US.ts

@@ -570,18 +570,17 @@ export default {
     // WebRTC / ICE
     webrtcSettings: 'WebRTC Settings',
     webrtcSettingsDesc: 'Configure STUN/TURN servers for NAT traversal',
-    usingPublicIceServers: 'Using public ICE servers',
-    publicIceServersHint: 'Leave empty to use built-in public STUN/TURN servers for NAT traversal',
+    publicIceServersHint: 'Empty uses Google public STUN, configure your own TURN for production',
     stunServer: 'STUN Server',
     stunServerPlaceholder: 'stun:stun.l.google.com:19302',
-    stunServerHint: 'Custom STUN server (leave empty to use public server)',
+    stunServerHint: 'Custom STUN server (leave empty to use Google public server)',
     turnServer: 'TURN Server',
     turnServerPlaceholder: 'turn:turn.example.com:3478',
-    turnServerHint: 'Custom TURN relay server (leave empty to use public server)',
+    turnServerHint: 'Custom TURN relay server (required for production)',
     turnUsername: 'TURN Username',
     turnPassword: 'TURN Password',
     turnPasswordConfigured: 'Password already configured. Leave empty to keep current password.',
-    turnCredentialsHint: 'Credentials for TURN server authentication (only needed for custom servers)',
+    turnCredentialsHint: 'Credentials for TURN server authentication',
     iceConfigNote: 'Note: Changes require reconnecting the WebRTC session to take effect.',
   },
   virtualKeyboard: {
@@ -703,7 +702,7 @@ export default {
       serverSettings: 'Server Settings',
       rendezvousServer: 'ID Server',
       rendezvousServerPlaceholder: 'hbbs.example.com:21116',
-      rendezvousServerHint: 'Leave empty to use public server',
+      rendezvousServerHint: 'Configure your RustDesk server address',
       relayServer: 'Relay Server',
       relayServerPlaceholder: 'hbbr.example.com:21117',
       relayServerHint: 'Relay server address, auto-derived from ID server if empty',
@@ -711,10 +710,6 @@ export default {
       relayKeyPlaceholder: 'Enter relay server key',
       relayKeySet: '••••••••',
       relayKeyHint: 'Authentication key for relay server (if server uses -k option)',
-      publicServerInfo: 'Public Server Info',
-      publicServerAddress: 'Server Address',
-      publicServerKey: 'Connection Key',
-      usingPublicServer: 'Using public server',
       deviceInfo: 'Device Info',
       deviceId: 'Device ID',
       deviceIdHint: 'Use this ID in RustDesk client to connect',