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/database.py

@@ -0,0 +1,49 @@
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.orm import DeclarativeBase
+
+from app.config import settings
+
+engine = create_async_engine(
+    settings.DATABASE_URL,
+    echo=settings.DEBUG,
+    connect_args={"check_same_thread": False},
+)
+
+async_session = async_sessionmaker(
+    bind=engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+async def get_db() -> AsyncSession:
+    """Dependency injection for async database sessions."""
+    async with async_session() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()
+
+
+async def init_db() -> None:
+    """Create all database tables."""
+    async with engine.begin() as conn:
+        from app.models import (  # noqa: F401
+            AlarmRecord,
+            AttendanceRecord,
+            BluetoothRecord,
+            CommandLog,
+            Device,
+            HeartbeatRecord,
+            LocationRecord,
+        )
+
+        await conn.run_sync(Base.metadata.create_all)