feat(expense): add persistent zero-entry receipt association

server/src/app/models/__init__.py

@@ -11,6 +11,7 @@ from app.models.ai_application_preview import AIApplicationPreviewDecision
 from app.models.ai_learning import AIDecision, AIDecisionFeedback, WorkflowOutcome
 from app.models.ai_memory import MemoryEntry, MemoryEvidenceLink
 from app.models.approval import ApprovalRecord
+from app.models.attachment_association_job import AttachmentAssociationJob
 from app.models.audit_log import AuditLog
 from app.models.auth_session import AuthSession
 from app.models.budget import BudgetAllocation, BudgetReservation, BudgetTransaction
@@ -53,6 +54,7 @@ __all__ = [
     "AgentTraceEvent",
     "AIApplicationPreviewDecision",
     "ApprovalRecord",
+    "AttachmentAssociationJob",
     "AuditLog",
     "AuthSession",
     "AIDecision",