feat(core-api): harden signed urls and llm rate limits

backend/core-api/test/app.test.js

@@ -1,10 +1,17 @@
-import test from 'node:test';
+import test, { beforeEach } from 'node:test';
 import assert from 'node:assert/strict';
 import request from 'supertest';
 import { createApp } from '../src/app.js';
+import { __resetLlmRateLimitForTests } from '../src/services/llm-rate-limit.js';
 
-process.env.AUTH_BYPASS = 'true';
-process.env.LLM_MOCK = 'true';
+beforeEach(() => {
+  process.env.AUTH_BYPASS = 'true';
+  process.env.LLM_MOCK = 'true';
+  process.env.SIGNED_URL_MOCK = 'true';
+  process.env.MAX_SIGNED_URL_SECONDS = '900';
+  process.env.LLM_RATE_LIMIT_PER_MINUTE = '20';
+  __resetLlmRateLimitForTests();
+});
 
 test('GET /healthz returns healthy response', async () => {
   const app = createApp();
@@ -34,7 +41,7 @@ test('POST /core/create-signed-url returns signed URL', async () => {
     .post('/core/create-signed-url')
     .set('Authorization', 'Bearer test-token')
     .send({
-      fileUri: 'gs://krow-workforce-dev-private/foo.pdf',
+      fileUri: 'gs://krow-workforce-dev-private/uploads/test-user/foo.pdf',
       expiresInSeconds: 300,
     });
 
@@ -44,6 +51,35 @@ test('POST /core/create-signed-url returns signed URL', async () => {
   assert.equal(typeof res.body.requestId, 'string');
 });
 
+test('POST /core/create-signed-url rejects non-owned path', async () => {
+  const app = createApp();
+  const res = await request(app)
+    .post('/core/create-signed-url')
+    .set('Authorization', 'Bearer test-token')
+    .send({
+      fileUri: 'gs://krow-workforce-dev-private/uploads/other-user/foo.pdf',
+      expiresInSeconds: 300,
+    });
+
+  assert.equal(res.status, 403);
+  assert.equal(res.body.code, 'FORBIDDEN');
+});
+
+test('POST /core/create-signed-url enforces expiry cap', async () => {
+  process.env.MAX_SIGNED_URL_SECONDS = '300';
+  const app = createApp();
+  const res = await request(app)
+    .post('/core/create-signed-url')
+    .set('Authorization', 'Bearer test-token')
+    .send({
+      fileUri: 'gs://krow-workforce-dev-private/uploads/test-user/foo.pdf',
+      expiresInSeconds: 301,
+    });
+
+  assert.equal(res.status, 400);
+  assert.equal(res.body.code, 'VALIDATION_ERROR');
+});
+
 test('POST /invokeLLM legacy alias works', async () => {
   const app = createApp();
   const res = await request(app)
@@ -59,3 +95,31 @@ test('POST /invokeLLM legacy alias works', async () => {
   assert.equal(typeof res.body.result, 'object');
   assert.equal(typeof res.body.model, 'string');
 });
+
+test('POST /core/invoke-llm enforces per-user rate limit', async () => {
+  process.env.LLM_RATE_LIMIT_PER_MINUTE = '1';
+  const app = createApp();
+
+  const first = await request(app)
+    .post('/core/invoke-llm')
+    .set('Authorization', 'Bearer test-token')
+    .send({
+      prompt: 'hello',
+      responseJsonSchema: { type: 'object' },
+      fileUrls: [],
+    });
+
+  const second = await request(app)
+    .post('/core/invoke-llm')
+    .set('Authorization', 'Bearer test-token')
+    .send({
+      prompt: 'hello again',
+      responseJsonSchema: { type: 'object' },
+      fileUrls: [],
+    });
+
+  assert.equal(first.status, 200);
+  assert.equal(second.status, 429);
+  assert.equal(second.body.code, 'RATE_LIMITED');
+  assert.equal(typeof second.headers['retry-after'], 'string');
+});