Companion: say which profile raw and channel data arrived on

MeshCore Open TAK labels a MediaMesh photo or voice clip "Received via
MediaMesh", "via main mesh" or both. Wadamesh standalones tell the
app the profile in a frame byte stock firmware leaves reserved; a
Cascade companion left it unset, so the app showed nothing.

While radio2 is on (rx or rxtx):
- PUSH_CODE_RAW_DATA (0x84) byte 3: 0xA0 primary, 0xA1 radio2
  (stock 0xFF).
- RESP_CODE_CHANNEL_DATA_RECV (0x1B) byte 2: the same (stock 0).
With radio2 off, or for a packet from the UDP bridge, the stock values
stay, so existing clients see no change.

Test: test/test_companion_rx_via.py (in run-unit-tests); the two
harnesses that compile these handlers get a stub.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011i5tJJtj95MB4oUgncCUe5

.github/workflows/run-unit-tests.yml

@@ -588,6 +588,7 @@ jobs:
           python3 -B test/test_companion_prefs_transactions.py -v
           python3 -B test/test_companion_primary_radio_persistence.py -v
           python3 -B test/test_companion_response_bounds.py -v
+          python3 -B test/test_companion_rx_via.py -v
           python3 -B test/test_companion_ack_delivery.py -v
           python3 -B test/test_companion_lost_reply.py -v
           python3 -B test/test_companion_delayed_reply_delivery.py -v