Fix CI: exclude test files from lint, mock db.js in jira test for runner env

backend/__tests__/jira-route-removal.test.js

@@ -28,6 +28,11 @@ jest.mock('../middleware/auth', () => ({
 // Mock the audit log helper to be a no-op.
 jest.mock('../helpers/auditLog', () => jest.fn());
 
+// Mock the db module to avoid requiring DATABASE_URL in CI
+jest.mock('../db', () => ({
+  query: jest.fn(() => Promise.resolve({ rows: [] })),
+}));
+
 // Mock the jiraApi helper — mark it as not configured so routes return 503
 // (which is fine; we only care that they are NOT 404).
 jest.mock('../helpers/jiraApi', () => ({