Add body_yaw parameter to REST API move endpoints

This change exposes the body_yaw parameter, which was already supported
in the Python SDK's goto_target() method, through the REST API endpoints.

Changes:
- Add body_yaw parameter to GotoModelRequest model
- Add target_body_yaw parameter to FullBodyTarget model
- Update /api/move/goto endpoint to pass body_yaw to backend
- Update /api/move/set_target endpoint to support body_yaw
- Add examples in JSON schema for both models

The body_yaw parameter allows controlling the rotation of the robot's
body around the vertical axis, enabling more expressive movements.

Tested with Mujoco simulator using curl commands to verify:
- Setting body_yaw alone works correctly
- Setting body_yaw together with head_pose works correctly
- Using body_yaw in set_target endpoint works correctly

Author: iizukak

src/reachy_mini/daemon/app/models.py

@@ -114,6 +114,7 @@ class FullBodyTarget(BaseModel):
 
     target_head_pose: AnyPose | None = None
     target_antennas: tuple[float, float] | None = None
+    target_body_yaw: float | None = None
     timestamp: datetime | None = None
 
     model_config = {
@@ -129,6 +130,7 @@ class FullBodyTarget(BaseModel):
                         "yaw": 0.0,
                     },
                     "target_antennas": [0.0, 0.0],
+                    "target_body_yaw": 0.0,
                 }
             ]
         }

src/reachy_mini/daemon/app/routers/move.py

@@ -47,6 +47,7 @@ class GotoModelRequest(BaseModel):
 
     head_pose: AnyPose | None = None
     antennas: tuple[float, float] | None = None
+    body_yaw: float | None = None
     duration: float
     interpolation: InterpolationMode = InterpolationMode.MINJERK
 
@@ -63,6 +64,7 @@ class GotoModelRequest(BaseModel):
                         "yaw": 0.0,
                     },
                     "antennas": [0.0, 0.0],
+                    "body_yaw": 0.0,
                     "duration": 2.0,
                     "interpolation": "minjerk",
                 },
@@ -152,6 +154,7 @@ async def goto(
         backend.goto_target(
             head=goto_req.head_pose.to_pose_array() if goto_req.head_pose else None,
             antennas=np.array(goto_req.antennas) if goto_req.antennas else None,
+            body_yaw=goto_req.body_yaw,
             duration=goto_req.duration,
         )
     )
@@ -232,6 +235,7 @@ async def set_target(
         if target.target_head_pose
         else None,
         antennas=np.array(target.target_antennas) if target.target_antennas else None,
+        body_yaw=target.target_body_yaw,
     )
     return {"status": "ok"}