fix: 补齐候选诊断环境与证据保护（09-06-release-gate-integrity）

server/src/routes/reimbursements.js

@@ -4820,5 +4820,6 @@ async function reimbursementRoutes(fastify) {
 module.exports = reimbursementRoutes;
 
 module.exports.__testables = {
+  ensureNonNegativeAmount,
   finalizeReimbursementSubmitSideEffects,
 };