[AZ-653] gimbal_controller ViewPro A40 vendor UDP transport (batch 10)

Implements the vendor wire protocol for the A40 gimbal (XOR-8 checksum,
not CRC16 — task spec corrected against ArduPilot AP_Mount_Viewpro.h):
frame encode/decode, typed FrameId/CameraCommand/ImageSensor, A1 angles,
C1 camera, C2 set-zoom command builders, and a tokio UdpSocket transport
with bounded retry, per-command deadline, and atomic vendor-fault
counters surfaced via faults()/health(). GimbalControllerHandle::set_pose
and zoom now ride the transport when wired; remain disabled when no
transport is bound. 32/32 gimbal_controller tests green; workspace test
suite green except for a pre-existing flake in
mission_executor::state_machine::ac3_bounded_retry_then_success that
reproduces only under parallel workspace test load (passes 5/5 in
isolation; flagged in batch 8 report, unrelated to this batch).

Co-authored-by: Cursor <cursoragent@cursor.com>

crates/gimbal_controller/Cargo.toml

@@ -12,3 +12,8 @@ shared = { workspace = true }
 tokio = { workspace = true }
 tracing = { workspace = true }
 serde = { workspace = true }
+thiserror = { workspace = true }
+async-trait = { workspace = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["test-util"] }