fix: use domain names for API access, China IP for LiveKit

Flutter app now uses https://it0api.szaiai.com (nginx reverse proxy)
instead of direct IP:port. LiveKit URL uses China IP 14.215.128.96
for lower latency from domestic mobile clients.

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

deploy/docker/docker-compose.yml

@@ -390,7 +390,7 @@ services:
       - OPENAI_TTS_VOICE=${OPENAI_TTS_VOICE:-coral}
       - LIVEKIT_API_KEY=devkey
       - LIVEKIT_API_SECRET=devsecret
-      - LIVEKIT_WS_URL=ws://154.84.135.121:7880
+      - LIVEKIT_WS_URL=ws://14.215.128.96:7880
     healthcheck:
       test: ["CMD-SHELL", "python3 -c \"import urllib.request; urllib.request.urlopen('http://localhost:3008/docs')\""]
       interval: 30s

it0_app/lib/core/config/app_config.dart

@@ -21,9 +21,9 @@ class AppConfig {
   );
 
   factory AppConfig.production() => const AppConfig(
-    apiBaseUrl: 'http://154.84.135.121:18000',
-    wsBaseUrl: 'ws://154.84.135.121:18000',
-    livekitUrl: 'ws://154.84.135.121:7880',
+    apiBaseUrl: 'https://it0api.szaiai.com',
+    wsBaseUrl: 'wss://it0api.szaiai.com',
+    livekitUrl: 'ws://14.215.128.96:7880',
     environment: 'production',
   );
 }