把存储的 yaw 上限归一到 ±180

yaw 台转 ±180，实测点的第二组精确解落在 118° 之外：旧文件里的 ±90 会让求解器把位姿算成可达、运动守卫却拒绝这段 yaw，操作员看到的就是“到不了”。加载时把求解器与守卫两种写法的 yaw 上限一起归一，pitch 包络此前已按同一理由处理。

apps/autocal/tests/test_kinematics.py

@@ -363,6 +363,42 @@ def test_the_yaw_limit_is_respected():
         assert abs(pose.yaw_deg) <= 90.0 + 1e-6
 
 
+def test_the_full_yaw_travel_keeps_the_second_solution_of_a_measured_point():
+    """±180 is what keeps "cannot reach" from being reported for an aligned pose.
+
+    ``docs/motion-correction-plan.zh.md`` measures a point at (-2.698, 5.186, 18.228)
+    with normal (-0.343, 0.699, 0.627). It has two exact solutions — -61.319°/+45.636°
+    and +118.681°/-45.636° — and the second sits outside the ±90 note this bench was
+    once configured with. At ±180 both branches are reachable, so a change in which
+    branch is preferred cannot strand the point on "cannot reach".
+    """
+    point = np.array([-2.698, 5.186, 18.228])
+    normal = np.array([-0.343, 0.699, 0.627])
+    wide = PlatformStack(yaw_limit_deg=180.0, pitch_limit_deg=90.0)
+    narrow = PlatformStack(yaw_limit_deg=90.0, pitch_limit_deg=90.0)
+
+    unit = wide.setup_normal(normal)
+    unit = unit / float(np.linalg.norm(unit))
+    wide_branches = wide.alignment_branches(unit, wide.tool_direction)
+    narrow_branches = narrow.alignment_branches(unit, narrow.tool_direction)
+
+    assert {round(branch.yaw_deg, 3) for branch in wide_branches} == {-61.319, 118.681}
+    assert all(branch.in_range for branch in wide_branches)
+    assert sum(branch.in_range for branch in narrow_branches) == 1, (
+        "±90 was expected to drop one of the two exact solutions"
+    )
+    assert wide.solve(point, normal).in_range
+
+
+def test_a_yaw_limit_past_the_trunnion_travel_is_capped():
+    """The stage turns ±180. A stored 360 must not widen the envelope."""
+    stack = PlatformStack(yaw_limit_deg=360.0, pitch_limit_deg=90.0)
+    assert stack._yaw_limit_effective() == 180.0  # the cap lives here, not in the caller
+    for normal in NORMALS:
+        pose = stack.solve(np.array([0.0, 5.0, 0.0]), normal)
+        assert abs(pose.yaw_deg) <= 180.0 + 1e-6
+
+
 def test_the_pitch_limit_is_respected():
     stack = PlatformStack(pitch_limit_deg=45.0)
     for normal in NORMALS: