Implement Phase 8: Rig Relocation and Component Modularization

- Moved the rig scene from `res://master_rig.tscn` to `res://scenes/stickman_rig.tscn`, preserving its UID.
- Split the `StickmanRig` controller into three components: `StickmanLocomotion`, `StickmanRagdoll`, and `StickmanActionRunner`.
- Updated the architecture to ensure `StickmanRig` acts as the public facade for the new components.
- Created a new test suite `test_phase8_rig_modularization.gd` to verify the integrity of the relocated rig and its components.
- Added checks for scene loading, component resolution, action queue delegation, and state authority.

scripts/create_animations.gd

@@ -25,7 +25,7 @@ const POSE_PATHS: Dictionary = {
 const POSE_MARKERS: Array[String] = ["Torso", "Head", "Left_Hand", "Right_Hand", "Left_Leg", "Right_Leg"]
 
 ## Pose templates (rig-local). POSE_DOWN is a generic "lying on back" rest pose;
-## POSE_STANDING matches master_rig.tscn's authored IK-target defaults. The
+## POSE_STANDING matches scenes/stickman_rig.tscn's authored IK-target defaults. The
 ## baked stand_up is an authored reference only — runtime recovery tweens the
 ## IK targets directly from the captured ragdoll pose instead.
 const POSE_DOWN: Dictionary = {