Update Hunter sprint tuning, animations and scene authoring

Content/authoring changes:
- Hunter prefab: set sprintSpeedMultiplier override to 2
- Paintman-Star animation + UMotion project edits
- SampleScene: prefab override / FirstPersonTarget cleanup

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Prefabs/Hunter.prefab

@@ -12,6 +12,10 @@ PrefabInstance:
       propertyPath: scale
       value: 2.5
       objectReference: {fileID: 0}
+    - target: {fileID: 1035623159758896108, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
+      propertyPath: sprintSpeedMultiplier
+      value: 2
+      objectReference: {fileID: 0}
     - target: {fileID: 5384024074013944205, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
       propertyPath: m_Name
       value: Hunter