Expense Approval Service

Backend service handling all approval and rejection mutations for expense claims. Wraps each decision in a database transaction that atomically updates the expense_claims row (status, approved_by, approved_at, rejection_reason) and inserts an audit log entry, then enqueues a notification event to the claimant. Enforces role authorization (Coordinator and Org Admin only) and processes bulk-approve batches as a single transaction to avoid N+1 API calls.

Feature: Expense Approval Queue

expense-approval-service

• Validate that the authenticated approver has Coordinator or Org Admin role for the claim's organization
• Atomically update claim status and record approver identity, timestamp, and optional rejection comment
• Write audit log entry for every approval or rejection decision
• Enqueue push and email/SMS notification event to the claimant upon decision
• Process bulk-approve batch in a single database transaction with per-item validation