feat: add mqtt pipeline tables and models

backend/tests/mqtt/test_models.py

@@ -0,0 +1,21 @@
+from sqlmodel import Session, SQLModel, create_engine
+
+from app.models import TerminalMessageRaw
+
+
+def test_terminal_message_raw_model_can_persist() -> None:
+    engine = create_engine("sqlite://")
+    SQLModel.metadata.create_all(engine)
+
+    with Session(engine) as session:
+        row = TerminalMessageRaw(
+            device_id="device-001",
+            topic="terminal/device-001/raw",
+            payload_bytes=b"$GPGGA,123519,3723.2475,N,12158.3416,W,1,12,0.8,10.0,M,-25.0,M,,*65\r\n",
+        )
+        session.add(row)
+        session.commit()
+        session.refresh(row)
+
+    assert row.id is not None
+    assert row.parse_status == "pending"