feat: KKS P240/P241 蓝牙工牌管理系统初始提交

FastAPI + SQLAlchemy + asyncio TCP 服务器，支持设备管理、实时定位、
告警、考勤打卡、蓝牙记录、指令下发、TTS语音播报等功能。

app/services/tcp_command_service.py

@@ -0,0 +1,31 @@
+"""
+TCP Command Service — Abstraction layer for sending commands to devices via TCP.
+
+Breaks the circular import between routers/commands.py and tcp_server.py
+by lazily importing tcp_manager only when needed.
+"""
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+def _get_tcp_manager():
+    """Lazily import tcp_manager to avoid circular imports."""
+    from app.tcp_server import tcp_manager
+    return tcp_manager
+
+
+def is_device_online(imei: str) -> bool:
+    """Check if a device is currently connected via TCP."""
+    return imei in _get_tcp_manager().connections
+
+
+async def send_command(imei: str, command_type: str, command_content: str) -> bool:
+    """Send an online command (0x80) to a connected device."""
+    return await _get_tcp_manager().send_command(imei, command_type, command_content)
+
+
+async def send_message(imei: str, message: str) -> bool:
+    """Send a text message (0x82) to a connected device."""
+    return await _get_tcp_manager().send_message(imei, message)