feat(backend): persist CasAdjustment rows from 835 SVC.adjustments

backend/src/cyclone/store.py

@@ -167,6 +167,12 @@ def _remittance_835_row(cp: ClaimPayment, batch_id: str) -> Remittance:
     """Build a Remittance ORM row from a ClaimPayment. NOT yet persisted."""
     received_at = utcnow()
     # Adjustment amount: sum the CAS rows for the first service line.
+    # NOTE: This is a best-effort placeholder used until the reconciliation
+    # pass (T10) overwrites it from the persisted CasAdjustment rows. The
+    # authoritative value comes from `reconcile.run()`, which sums
+    # ``CasAdjustment.amount`` per ``remittance_id`` and writes the result
+    # back to ``Remittance.adjustment_amount``. We keep this stub so the
+    # row has a sane value if reconciliation is disabled or fails.
     adjustment = Decimal("0")
     if cp.service_payments:
         sp = cp.service_payments[0]
@@ -194,6 +200,27 @@ def _remittance_835_row(cp: ClaimPayment, batch_id: str) -> Remittance:
     )
 
 
+def _cas_adjustment_row(adj, remittance_id: str) -> "db.CasAdjustment":
+    """Build a CasAdjustment ORM row from a ClaimAdjustment. NOT yet persisted.
+
+    One row per SVC-level CAS adjustment is persisted so the T10
+    reconcile aggregator can compute ``Remittance.adjustment_amount``
+    as ``SUM(CasAdjustment.amount) WHERE remittance_id = ...``.
+
+    ``quantity`` is optional in the X12 CAS spec; we coerce to Decimal
+    only when present to keep the column NULL for the common no-QTY case.
+    """
+    from cyclone.db import CasAdjustment
+    quantity = getattr(adj, "quantity", None)
+    return CasAdjustment(
+        remittance_id=remittance_id,
+        group_code=adj.group_code,
+        reason_code=adj.reason_code,
+        amount=Decimal(str(adj.amount)),
+        quantity=Decimal(str(quantity)) if quantity is not None else None,
+    )
+
+
 # ---------------------------------------------------------------------------
 # UI mappers: ORM rows → simpler UI types.
 # ---------------------------------------------------------------------------
@@ -471,7 +498,16 @@ class CycloneStore:
                             cp.payer_claim_control_number, record.id,
                         )
                         continue
-                    s.add(_remittance_835_row(cp, record.id))
+                    remit_row = _remittance_835_row(cp, record.id)
+                    s.add(remit_row)
+                    # Flush so remit_row.id (FK target of cas_adjustments) is
+                    # populated. SQLAlchemy assigns the PK on flush; without
+                    # this the CasAdjustment inserts below would reference an
+                    # unset id and violate the FK.
+                    s.flush()
+                    for svc in cp.service_payments:
+                        for adj in svc.adjustments:
+                            s.add(_cas_adjustment_row(adj, remit_row.id))
                     s.add(ActivityEvent(
                         ts=record.parsed_at,
                         kind="remit_received",