Align state AGI-band convention with main SOI loop ([lower, upper)) (#775)

`_add_state_agi_metric_columns` used `(agi > lower) & (agi <= upper)`
(left-exclusive, right-inclusive) while the main SOI loop in
`build_loss_matrix` at line 425 uses `(agi >= lower) & (agi < upper)`
(left-inclusive, right-exclusive). Both loops read from the same SOI
CSV; the SOI data is published on the half-open `[lower, upper)`
convention, so the state-band loop was misclassifying records that
sit exactly on bucket boundaries.

Switch to the `[lower, upper)` convention for consistency with both
the main SOI loop and the underlying data.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: MaxGhenis

changelog.d/fix-agi-band-boundary-convention.fixed.md

@@ -0,0 +1 @@
+Use the [lower, upper) AGI-band boundary convention in the state AGI metric loop, matching the main SOI loop in build_loss_matrix.

policyengine_us_data/utils/loss.py

@@ -1033,7 +1033,10 @@ def _add_agi_metric_columns(
         band = get_agi_band_label(lower, upper)
 
         in_state = state == r.GEO_NAME
-        in_band = (agi > lower) & (agi <= upper)
+        # Use the same [lower, upper) boundary convention as the main SOI
+        # loop in build_loss_matrix() (the SOI targets use half-open bands
+        # starting at the lower bound).
+        in_band = (agi >= lower) & (agi < upper)
 
         if r.IS_COUNT:
             metric = (in_state & in_band & (agi > 0)).astype(float)