fix: align navigation contract and readiness handling

ros2/bt_skill_interfaces/action/Navigate.action

@@ -1,33 +1,30 @@
-# Preserved outer interface from BT DR pp13-14. Canonical ROS2 type: Navigate.
+# Navigation contract: trace and stop evidence retained across all attempts.
+# Enum values are explicit; both peers must build this same interface package.
 bt_skill_interfaces/TaskTrace trace
 geometry_msgs/PoseStamped target_pose
 float64 position_tolerance
-float64 orientation_tolerance
+float64 yaw_tolerance
 builtin_interfaces/Duration timeout
 ---
-bt_skill_interfaces/ExecutionResult result
-bool pose_valid
+bt_skill_interfaces/NavigationResult result
+bool final_pose_valid
 geometry_msgs/PoseStamped final_pose
-bool errors_valid
 float64 final_position_error
-float64 final_orientation_error
+float64 final_yaw_error
 ---
-uint8 CHECKING=0
-uint8 PLANNING=1
+uint8 ACCEPTED=0
+uint8 CHECKING=1
 uint8 NAVIGATING=2
-uint8 WAITING_OBSTACLE=3
-uint8 RECOVERING=4
-uint8 ARRIVING=5
-uint8 STOPPING=6
+uint8 BLOCKED=3
+uint8 STOPPING=4
 builtin_interfaces/Time stamp
 uint32 sequence
 uint8 phase
-bool pose_valid
+bool current_pose_valid
 geometry_msgs/PoseStamped current_pose
-bool errors_valid
+bool error_valid
 float64 position_error
-float64 orientation_error
-bool blocked_valid
+float64 yaw_error
 bool blocked
 builtin_interfaces/Duration elapsed_time
 string message