franka_ros2 v2.5.0

Requires libfranka >= 0.20.4 and franka_description >= 2.8.0 requires ROS 2 Humble

• chore: split the gazebo sources into two packages, franka_gazebo_bringup
  (launch files, worlds, robot descriptions, controller configs) and
  franka_gazebo_hardware (the gz_ros2_control gravity-compensation system plugin,
  franka_gazebo_hardware/GazeboGravityCompensationSystem). The public
  ros2 launch franka_gazebo_bringup ... command is unchanged.

• fix: franka_gazebo_bringup: fix launch file for gazebo (use world without gravity by default for example controllers)
  Requires libfranka >= 0.20.4 and franka_description >= 2.7.0 requires ROS 2 Humble
  Requires libfranka >= 0.20.4 and franka_description >= 2.8.0(?) requires ROS 2 Jazzy

• feat: expose K_F_ext_hat_K as ForceTorqueSensor state interfaces (force.x/y/z,
  torque.x/y/z) on the <arm_prefix><robot_type>_tcp sensor, enabling direct wrench
  consumption at control frequency without a topic bridge.

• BREAKING CHANGE: collision_detected topic now uses best_effort QoS (SensorDataQoS);
  thread-safe atomics for collision state in example controllers.
  Subscribers using the default reliable QoS will no longer receive messages.
  To migrate, set the subscriber QoS to best_effort (SensorDataQoS):

• feat: Added franka_spine packages (franka_spine_msgs, franka_spine_server, franka_spine_examples) — ROS 2 action/service server for controlling the Franka Spine module

• docu: Added documentation for error recovery after an FCI error.

• refactor: Removed the dead auto_declare<std::string>("robot_description", "") parameter from the joint position/velocity example controllers - the URDF is obtained from robot_state_publisher via the parameters client, so the declaration was unused.

• chore: devcontainer container name now derives from the workspace folder basename (<folder>_humble) so variant clones no longer collide on a fixed container name.