fix(cli): disable depth unless verify/refine enabled

- Ensure default extrinsics calibration runs with depth mode NONE
- Depth is only enabled when --verify-depth or --refine-depth is set
- Document opt-in behavior in notepad

py_workspace/.sisyphus/notepads/depth-extrinsic-verify/learnings.md

@@ -79,3 +79,4 @@ The integration needs to:
   - Refinement only runs if sufficient valid depth points (>4) exist.
   - Refined pose (`T_refined`) replaces the original RANSAC mean pose in the output JSON if refinement is successful.
   - Original RANSAC stats remain in `stats` field, while refinement deltas are in `refine_depth`.
+- Opt-in depth behavior: Depth computation is now explicitly disabled in `calibrate_extrinsics.py` unless `--verify-depth` or `--refine-depth` is set. This prevents unnecessary GPU/CPU overhead during standard extrinsic calibration.

py_workspace/calibrate_extrinsics.py

@@ -89,6 +89,9 @@ def main(
     }
     sl_depth_mode = depth_mode_map.get(depth_mode, sl.DEPTH_MODE.NONE)
 
+    if not (verify_depth or refine_depth):
+        sl_depth_mode = sl.DEPTH_MODE.NONE
+
     # 1. Load Marker Geometry
     try:
         marker_geometry = load_marker_geometry(markers)