feat: async task pipeline for media and llm workflows

.env.example

@@ -12,6 +12,7 @@ VITE_OAUTH_PORTAL_URL=
 VITE_FRONTEND_FORGE_API_URL=
 VITE_FRONTEND_FORGE_API_KEY=
 LOCAL_STORAGE_DIR=/data/app/storage
+APP_PUBLIC_BASE_URL=https://te.hao.work/
 
 # Compose MySQL
 MYSQL_DATABASE=tennis_training_hub
@@ -23,6 +24,9 @@ MYSQL_ROOT_PASSWORD=replace-with-root-password
 LLM_API_URL=https://one.hao.work/v1/chat/completions
 LLM_API_KEY=replace-with-llm-api-key
 LLM_MODEL=qwen3.5-plus
+LLM_VISION_API_URL=https://one.hao.work/v1/chat/completions
+LLM_VISION_API_KEY=replace-with-llm-api-key
+LLM_VISION_MODEL=qwen3-vl-235b-a22b
 LLM_MAX_TOKENS=32768
 LLM_ENABLE_THINKING=0
 LLM_THINKING_BUDGET=128
@@ -32,3 +36,5 @@ VITE_MEDIA_BASE_URL=/media
 
 # Local app-to-media proxy for development or direct container access
 MEDIA_SERVICE_URL=http://127.0.0.1:8081
+BACKGROUND_TASK_POLL_MS=3000
+BACKGROUND_TASK_STALE_MS=300000