Wire ADS-B end to end: secondary-sdr container running dump1090

node-26#9. New secondary-sdr-container claims the node's SECOND physical
SDR (RTL-SDR index 1 — op25 always claims index 0; no serial-based binding
yet, same gap op25 itself has). Its control API (start/stop/status/data,
mirroring op25_controller.py) launches dump1090 in adsb mode and exposes
the decoded aircraft.json snapshot; AIS mode 400s until it's wired next.

edge-node: on_config_push starts/stops it when secondary_sdr_mode changes,
lifespan resumes it after a restart if already configured, and a new
telemetry_uplink_loop polls its /secondary/data every 10s and POSTs
non-empty snapshots to C2's new /telemetry/adsb (same bearer-key pattern
call_recorder.py already uses for audio upload).

UNVERIFIED: this container has not been built or run against real hardware
in this session (sandboxed authoring machine, no docker) — dump1090's
--write-json field names are believed correct from its docs but not
confirmed against a real capture. Build + hardware smoke test before this
reaches a real node.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docker-compose.yml

@@ -32,6 +32,21 @@ services:
     depends_on:
       - icecast
 
+  # Claims the node's SECOND physical SDR (op25 always claims the first).
+  # Only useful if secondary_sdr_mode is set to adsb|ais via the edge-node
+  # config; otherwise it just sits idle answering /secondary/status. See
+  # node-26#9. Same network/device access as op25 for the same reason: it
+  # needs the raw USB device, not a virtualized one.
+  secondary-sdr:
+    image: ${IMAGE_REGISTRY:-git.vpn.cusano.net}/${DOCKER_ORG:-logan}/${DOCKER_REPO:-node-26}/secondary-sdr:latest
+    build: ./secondary-sdr-container
+    restart: unless-stopped
+    privileged: true
+    network_mode: host
+    env_file: .env
+    volumes:
+      - /dev:/dev
+
   edge-node:
     image: ${IMAGE_REGISTRY:-git.vpn.cusano.net}/${DOCKER_ORG:-logan}/${DOCKER_REPO:-node-26}/edge-node:latest
     build: ./drb-edge-node