imu: the WT61 on any USB-UART adapter, in the car's frame, on yukart/imu/*

Finds the module itself (every non-modem adapter, 115200 then 9600), so the
adapter can be swapped. Mounting by --forward/--right; attitude from a
complementary filter on gravity (gyro through motion, accelerometer near 1 g);
gravity removed from acceleration; yaw rate left-positive. Never writes to
the module. dialout via SupplementaryGroups.

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

Cargo.toml

@@ -2,7 +2,7 @@
 name = "svc-core"
 version = "0.1.0"
 edition = "2021"
-description = "Acquisition and processing cluster: recorder, decoder, gnss, orin-status and obd-poller now; can-bridge later"
+description = "Acquisition and processing cluster: recorder, decoder, gnss, imu, orin-status and obd-poller now; can-bridge later"
 publish = false
 
 [[bin]]
@@ -25,6 +25,10 @@ path = "src/decoder/main.rs"
 name = "gnss"
 path = "src/gnss/main.rs"
 
+[[bin]]
+name = "imu"
+path = "src/imu/main.rs"
+
 [[bin]]
 name = "bus-bench"
 path = "src/bus-bench/main.rs"