obd-poller: OBD-II mode 01, the single CAN writer; recorder keeps its values

obd-poller asks 0x7DF for the nine obd2 signals, only while the bus is alive,
and publishes envelopes stamped with the reply's kernel time. The recorder
subscribes to yukart/vehicle/* and writes vehicle.ndjson beside the frames.
Tested against a fake ECU on vcan0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

scripts/deploy-recorder.sh

@@ -13,7 +13,7 @@ cd "$(dirname "$0")/.."
 TARGET=aarch64-unknown-linux-gnu
 BIN="target/$TARGET/release/recorder"
 
-cargo build --release --target "$TARGET"
+cargo build --release --target "$TARGET" --bin recorder
 scripts/check-glibc.sh "$BIN"
 
 # Binary lives under ~/infra per the host repo's guidelines; /usr/local/bin gets a symlink.