feat(api): add agent mail and reservations routes

tests/api/agents-mail.test.ts

@@ -0,0 +1,67 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { GET as getMail, POST as postMail, PATCH as patchMail } from '../../src/app/api/agents/mail/route';
+import { GET as getReservations } from '../../src/app/api/agents/reservations/route';
+
+async function readJson(response: Response): Promise<any> {
+  const text = await response.text();
+  return text ? JSON.parse(text) : {};
+}
+
+test('GET /api/agents/mail returns AGENT_NOT_FOUND for unknown agent', async () => {
+  const response = await getMail(new Request('http://localhost/api/agents/mail?agent=nonexistent'));
+  const data = await readJson(response);
+  assert.equal(response.status, 404);
+  assert.equal(data.ok, false);
+  assert.equal(data.error?.code, 'AGENT_NOT_FOUND');
+});
+
+test('POST /api/agents/mail returns structured error on missing sender/recipient', async () => {
+  const response = await postMail(
+    new Request('http://localhost/api/agents/mail', {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({
+        from: 'unknown',
+        to: 'missing',
+        bead: 'bb-123',
+        category: 'INFO',
+        subject: 'hello',
+        body: 'world',
+      }),
+    }),
+  );
+  const data = await readJson(response);
+  assert.equal(response.status, 404);
+  assert.equal(data.ok, false);
+  assert.equal(typeof data.error?.code, 'string');
+  assert.equal(typeof data.error?.message, 'string');
+});
+
+test('PATCH /api/agents/mail validates action', async () => {
+  const response = await patchMail(
+    new Request('http://localhost/api/agents/mail', {
+      method: 'PATCH',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({
+        action: 'nope',
+        agent: 'x',
+        message: 'y',
+      }),
+    }),
+  );
+  const data = await readJson(response);
+  assert.equal(response.status, 400);
+  assert.equal(data.ok, false);
+  assert.equal(data.error?.code, 'INVALID_ACTION');
+});
+
+test('GET /api/agents/reservations returns AGENT_NOT_FOUND for unknown agent', async () => {
+  const response = await getReservations(
+    new Request('http://localhost/api/agents/reservations?agent=nonexistent'),
+  );
+  const data = await readJson(response);
+  assert.equal(response.status, 404);
+  assert.equal(data.ok, false);
+  assert.equal(data.error?.code, 'AGENT_NOT_FOUND');
+});