fix: drop broken loan_events FK from loan_disputes migration

backend/src/__tests__/loanDisputesSchema.test.ts

@@ -0,0 +1,42 @@
+import { describe, it, expect, beforeAll } from '@jest/globals';
+import { query } from '../db/connection.js';
+
+let databaseAvailable = false;
+
+beforeAll(async () => {
+  try {
+    await query('SELECT 1');
+    databaseAvailable = true;
+  } catch {
+    databaseAvailable = false;
+  }
+});
+
+const describeIf = (name: string, fn: () => void) => {
+  if (databaseAvailable) {
+    describe(name, fn);
+  } else {
+    describe.skip(`${name} (skipped: no database)`, fn);
+  }
+};
+
+describeIf('loan_disputes schema', () => {
+  it('should successfully insert a loan dispute against the schema', async () => {
+    const result = await query(
+      `INSERT INTO loan_disputes (loan_id, borrower, reason) VALUES ($1, $2, $3) RETURNING id`,
+      [100, 'G_DISPUTE_TEST_BORROWER', 'Test dispute reason'],
+    );
+
+    expect(result.rows.length).toBe(1);
+    expect(result.rows[0].id).toBeDefined();
+
+    const selectResult = await query(`SELECT * FROM loan_disputes WHERE id = $1`, [
+      result.rows[0].id,
+    ]);
+    expect(selectResult.rows[0].loan_id).toBe(100);
+    expect(selectResult.rows[0].borrower).toBe('G_DISPUTE_TEST_BORROWER');
+    expect(selectResult.rows[0].status).toBe('open');
+
+    await query('DELETE FROM loan_disputes WHERE id = $1', [result.rows[0].id]);
+  });
+});