修正基线系标定默认：机械初值、地面ROI与航向偏移可配，并补充G90窗导出与契约测试

Co-authored-by: Cursor <cursoragent@cursor.com>

run/rtk_lidar_mechanical_initial.json

@@ -0,0 +1,23 @@
+{
+  "schema_version": 1,
+  "convention": "T_RTK_lidar maps raw LiDAR points into the RTK baseline frame (X = rawHeading baseline, Y left, Z up; heading_offset_deg = 0)",
+  "translation_m": [
+    0.414179474,
+    0.210859360,
+    0.004000001
+  ],
+  "rotation_rpy_deg_xyz": [
+    0.0,
+    0.0,
+    90.0
+  ],
+  "matrix_4x4": [
+    [0.0, -1.0, 0.0, 0.414179474],
+    [1.0, 0.0, 0.0, 0.210859360],
+    [0.0, 0.0, 1.0, 0.004000001],
+    [0.0, 0.0, 0.0, 1.0]
+  ],
+  "use": "Final AX=XB solver initialization only; never use for LiDAR pair registration",
+  "yaw_note": "≈90 deg yaw is expected when LiDAR X is vehicle-forward and the dual-antenna baseline is left-right",
+  "z_note": "CAD/mechanical z only; final z is constrained by measured GGA/ANT1 phase-center height above ground"
+}