feat(backend): add Remittance + CasAdjustment ORM models

backend/src/cyclone/db.py

@@ -20,11 +20,13 @@ from typing import Optional
 
 import sqlalchemy as sa
 from sqlalchemy import (
+    Boolean,
     Date,
     DateTime,
     Enum,
     ForeignKey,
     Index,
+    Integer,
     Numeric,
     String,
     Text,
@@ -223,11 +225,6 @@ class Claim(Base):
     )
 
 
-# Minimal stub for forward relationship/FK resolution. The full Remittance
-# model (with payer_claim_control_number, status_code, total_charge, etc.)
-# is defined in Task 5 and will replace this stub. The stub declares only
-# the columns needed for `Batch.remittances` relationship resolution and
-# `Claim.matched_remittance_id` FK metadata resolution.
 class Remittance(Base):
     __tablename__ = "remittances"
 
@@ -235,4 +232,48 @@ class Remittance(Base):
     batch_id: Mapped[str] = mapped_column(
         String(32), ForeignKey("batches.id", ondelete="CASCADE"), nullable=False
     )
+    payer_claim_control_number: Mapped[str] = mapped_column(String(64), nullable=False)
+    claim_id: Mapped[Optional[str]] = mapped_column(
+        String(64), ForeignKey("claims.id"), nullable=True
+    )
+    status_code: Mapped[str] = mapped_column(String(4), nullable=False)
+    status_label: Mapped[Optional[str]] = mapped_column(String(32), nullable=True)
+    total_charge: Mapped[Decimal] = mapped_column(Numeric(12, 2), nullable=False, default=Decimal("0"))
+    total_paid: Mapped[Decimal] = mapped_column(Numeric(12, 2), nullable=False, default=Decimal("0"))
+    patient_responsibility: Mapped[Optional[Decimal]] = mapped_column(Numeric(12, 2), nullable=True)
+    adjustment_amount: Mapped[Decimal] = mapped_column(Numeric(12, 2), nullable=False, default=Decimal("0"))
+    received_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+    service_date: Mapped[Optional[date]] = mapped_column(Date, nullable=True)
+    is_reversal: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
+    raw_json: Mapped[Optional[dict]] = mapped_column(JSONText, nullable=True)
+
     batch: Mapped["Batch"] = relationship(back_populates="remittances")
+    cas_adjustments: Mapped[list["CasAdjustment"]] = relationship(
+        back_populates="remittance", cascade="all, delete-orphan"
+    )
+
+    __table_args__ = (
+        UniqueConstraint("batch_id", "payer_claim_control_number", name="uq_remits_batch_pcn"),
+        Index("ix_remittances_claim_id", "claim_id"),
+        Index("ix_remittances_payer_claim_control_number", "payer_claim_control_number"),
+        Index("ix_remittances_status_code", "status_code"),
+    )
+
+
+class CasAdjustment(Base):
+    __tablename__ = "cas_adjustments"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    remittance_id: Mapped[str] = mapped_column(
+        String(64), ForeignKey("remittances.id", ondelete="CASCADE"), nullable=False
+    )
+    group_code: Mapped[str] = mapped_column(String(4), nullable=False)
+    reason_code: Mapped[str] = mapped_column(String(8), nullable=False)
+    amount: Mapped[Decimal] = mapped_column(Numeric(12, 2), nullable=False)
+    quantity: Mapped[Optional[Decimal]] = mapped_column(Numeric(10, 2), nullable=True)
+
+    remittance: Mapped["Remittance"] = relationship(back_populates="cas_adjustments")
+
+    __table_args__ = (
+        Index("ix_cas_adjustments_remittance_id", "remittance_id"),
+    )