feat: 接入 LogHive 远程日志系统

- 添加 LogHiveHandler，启动时自动挂载到 root logger
- 所有 logging 日志自动异步发送到 LogHive，不影响主业务
- vendored loghive-client 包，Docker 构建时自动安装
- API Key 缺失时自动跳过，不影响本地开发

app/main.py

@@ -22,6 +22,17 @@ async def lifespan(app: FastAPI):
         level=getattr(logging, settings.log_level),
         format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
     )
+    # LogHive 远程日志（仅当配置了 API Key 时启用）
+    if settings.loghive_api_key:
+        from loghive_client import LogHiveHandler
+        handler = LogHiveHandler(
+            project=settings.loghive_project,
+            api_key=settings.loghive_api_key,
+            endpoint=settings.loghive_endpoint,
+            level=logging.INFO,
+        )
+        logging.getLogger().addHandler(handler)
+        logging.info("LogHive 日志系统已连接")
     from app.scheduler.jobs import shutdown_scheduler, start_scheduler
     start_scheduler()
     yield