Update changelog with args sync, DRY sequential path, and thread-safe commits

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: baogorek

changelog_entry.yaml

@@ -5,3 +5,6 @@
     - Checkpointing mechanism to resume data builds and testing modules from last successful step in Modal runs.
     changed:
     - Removed duplicate run of test_local_area_calibration tests.
+    - Baked correct defaults into create_stratified_cps.py, removing hardcoded args from Makefile and Modal build.
+    - DRYed up sequential build path to iterate SCRIPT_OUTPUTS instead of a redundant list.
+    - Added thread-safe locking around volume.commit() for parallel checkpoint safety.