feat: implement mqtt ingestion, parsing, and archive pipeline

backend/app/mqtt/parsers/mixed.py

@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+from typing import Any
+
+from app.mqtt.parsers.nmea import parse_nmea_sentences
+from app.mqtt.parsers.rtcm import summarize_rtcm_types
+
+
+def parse_mixed_payload(payload: bytes) -> list[dict[str, Any]]:
+    events = parse_nmea_sentences(payload)
+
+    rtcm_types = summarize_rtcm_types(payload)
+    if rtcm_types:
+        events.append(
+            {
+                "event_type": "rtcm_summary",
+                "payload": {
+                    "rtcm_message_count": sum(rtcm_types.values()),
+                    "rtcm_types": rtcm_types,
+                },
+            }
+        )
+
+    return events