feat(expenses): add transactional expense case events

server/src/app/services/expense_claims.py

@@ -115,6 +115,7 @@ from app.services.expense_claim_constants import (
     TRAVEL_POLICY_HOTEL_NIGHT_PATTERN,
     STANDARD_ADJUSTMENT_RISK_SOURCE,
 )
+from app.services.expense_cases import ExpenseCaseService
 from app.services.expense_claim_risk_review import ExpenseClaimRiskReviewMixin
 from app.services.expense_amounts import (
     extract_amount_candidates,
@@ -645,6 +646,20 @@ class ExpenseClaimItemActionMixin:
 
         claim.risk_flags_json = dedupe_claim_risk_flags(claim.risk_flags_json)
 
+        self._expense_cases.record_claim_event(
+            claim,
+            event_type=("application_submitted" if is_application_claim else "claim_submitted"),
+            actor_id=current_user.username,
+            tenant_id=getattr(current_user, "tenant_id", None),
+            idempotency_key=(
+                f"submit:{claim.id}:{claim.submitted_at.isoformat()}"
+                if claim.submitted_at is not None
+                else f"submit:{claim.id}:{before_json.get('status') or 'draft'}"
+            ),
+            previous_status=str(before_json.get("status") or ""),
+            previous_approval_stage=str(before_json.get("approval_stage") or ""),
+        )
+
         self.db.commit()
         self.db.refresh(claim)
 
@@ -843,6 +858,20 @@ class ExpenseClaimItemActionMixin:
             business_stage="expense_application" if is_application_claim else "reimbursement",
         )
 
+        self._expense_cases.record_claim_event(
+            claim,
+            event_type=("application_returned" if is_application_claim else "claim_returned"),
+            actor_id=current_user.username,
+            tenant_id=getattr(current_user, "tenant_id", None),
+            idempotency_key=str(return_flag.get("return_event_id") or ""),
+            previous_status=previous_status,
+            previous_approval_stage=previous_stage,
+            extra_payload={
+                "reason": message,
+                "reason_codes": normalized_reason_codes,
+            },
+        )
+
         self.db.commit()
         self.db.refresh(claim)
 
@@ -862,6 +891,7 @@ class ExpenseClaimService(ExpenseClaimStandardAdjustmentMixin, ExpenseClaimItemA
     def __init__(self, db: Session) -> None:
         self.db = db
         self.audit_service = AuditLogService(db)
+        self._expense_cases = ExpenseCaseService(db)
         self._access_policy = ExpenseClaimAccessPolicy(db)
         self._attachment_storage = ExpenseClaimAttachmentStorage()
         self._attachment_presentation = ExpenseClaimAttachmentPresentation(self._attachment_storage)