Feature/hw13-ros2 - #13

Extends the provided antidrone_turret package with the turret control layer required by the assignment. Adds a ROS-independent decision core, the turret_controller_node, two aiming driver nodes, three new message types, unit tests, and the CMake/launch/YAML wiring. The starter package (target_track_publisher_node, actuator_node, provided interfaces, tracks, and provided_logic_test.cpp) is left untouched.

What was implemented

New message interfaces

• msg/GimbalCommand.msg — vertical aiming command (UP/CENTER/DOWN, target_y, error_y)
• msg/ServoCommand.msg — horizontal aiming command (LEFT/CENTER/RIGHT, target_x, error_x)
• msg/TurretStatus.msg — controller decision snapshot (target_state, action, trigger_state, confidence, distance_m)

Pure C++ logic (no rclcpp) — include/antidrone_turret/turret_controller.hpp

• evaluate_target → TARGET_NONE / TARGET_LOW_CONFIDENCE / TARGET_LOCKED
• make_servo_command → direction + error_x = x - 320
• make_gimbal_command → direction + error_y = 240 - y
• make_trigger_decision → TRIGGER_SKIP / TRIGGER_REQUESTED / TRIGGER_RELOADING
• build_turret_status → assembles the full TurretStatus

Nodes

• turret_controller_node — subscribes to /perception/target and /actuator/status, publishes /turret/status, /gimbal/cmd, /servo/cmd, and calls the /actuator/trigger service. Reads confidence_threshold and max_distance_m from YAML. The node is a thin wrapper: it only translates ROS messages to/from the pure logic and maps enums to message constants.
• gimbal_driver_node — subscribes to /gimbal/cmd and logs the typed command.
• yaw_servo_driver_node — subscribes to /servo/cmd and logs the typed command.

Trigger safety
A single fire request per engagement: a trigger_pending_ latch plus the last /actuator/status state prevent duplicate /actuator/trigger calls while the actuator is RELOADING. The latch is cleared once the actuator returns to READY.
Tests — test/turret_controller_test.cpp

At least one test per decision part: target evaluation, servo command, gimbal command, trigger decision (READY → REQUESTED, RELOADING → RELOADING, far → SKIP), and full TurretStatus assembly.
Build / launch / config

CMakeLists.txt: registered the three new interfaces, added executables for the three new nodes (ament_auto), linked cpp_typesupport_target, and added the new gtest target.
system.launch.py: added the three nodes (controller gets parameters=[config]; drivers run without parameters). All nodes honor the log_level argument.
config/sequence.yaml: turret_controller_node parameters (confidence_threshold: 0.8, max_distance_m: 30.0).