Calls: store every radio heard on a call; call_end writes srcaddr (server-26#304)

P1 of the radio-ID plan. The node now reports `radios`, one
{radio, start, end} per transmission, on /upload and on call_end. Both go
through app/internal/radios.py into `radios` + `radio_ids` on the call doc.
/upload writes them before the pipeline starts, because call_end arrives
after it.

call_end also writes srcaddr now. Only call_start used to, and the node
usually learns the talker after call_start, so most calls kept None and the
correlator's srcaddr match rarely fired. /upload fills srcaddr from the
latest radio when the doc has none.

Older nodes send neither field; nothing is blanked.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-c2-core/app/routers/upload.py

@@ -5,6 +5,7 @@ from fastapi import APIRouter, BackgroundTasks, UploadFile, File, Form, HTTPExce
 from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
 from app.internal.storage import upload_audio
 from app.internal import dedup
+from app.internal import radios
 from app.internal import firestore as fstore
 from app.internal import clock
 from app.internal.logger import logger
@@ -24,6 +25,7 @@ async def upload_call_audio(
     talkgroup_id: Optional[int] = Form(None),
     talkgroup_name: Optional[str] = Form(None),
     system_id: Optional[str] = Form(None),
+    radios_json: Optional[str] = Form(None, alias="radios"),
     credentials: Optional[HTTPAuthorizationCredentials] = Security(_bearer),
 ):
     """
@@ -101,6 +103,14 @@ async def upload_call_audio(
             updates = {"audio_gcs_uri": gcs_uri}
             if node and node.get("org_id"):
                 updates["org_id"] = node["org_id"]
+            # Every radio heard on the call (server-26#304). Written here, not
+            # only on call_end, because the pipeline below starts before the
+            # node publishes call_end.
+            radio_fields = radios.call_fields(radios_json)
+            updates.update(radio_fields)
+            if radio_fields and existing.get("srcaddr") is None:
+                # Same meaning call_end gives it: the latest talker.
+                updates["srcaddr"] = radio_fields["radios"][-1]["radio"]
             await fstore.doc_set("calls", call_id, updates)
         except Exception as e:
             logger.warning(f"Could not update call {call_id} with audio_gcs_uri: {e}")