Add snap to calibration targets, remove redundant files

- Add "snap" to variables filter in fit_calibration_weights.py to include
  National SNAP targets (in different stratum_group_id than 4)
- Remove redundant test_sparse_matrix_builder.py (tests consolidated in
  test_matrix_national_variation.py)
- Remove redundant build_calibration_matrix.py (functionality covered by
  fit_calibration_weights.py)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: baogorek

changelog_entry.yaml

@@ -2,10 +2,11 @@
   changes:
     added:
     - Support for health_insurance_premiums_without_medicare_part_b in local area calibration
-    - Test coverage for sparse matrix builder with person-level targets
     changed:
     - Removed dense reweighting path from enhanced CPS; only sparse (L0) weights are produced
     - Eliminated TEST_LITE and LOCAL_AREA_CALIBRATION flags; all datasets generated unconditionally
     - Merged data-local-area Makefile target into data target
+    removed:
+    - Redundant test_sparse_matrix_builder.py (tests consolidated in test_matrix_national_variation.py)
     fixed:
     - Versioning workflow now runs uv lock after version bump to keep uv.lock in sync

policyengine_us_data/datasets/cps/local_area_calibration/build_calibration_matrix.py

@@ -106,7 +106,10 @@
     sim,
     target_filter={
         "stratum_group_ids": [4],
-        "variables": ["health_insurance_premiums_without_medicare_part_b"],
+        "variables": [
+            "health_insurance_premiums_without_medicare_part_b",
+            "snap",
+        ],
     },
 )