Fix test failures caused by @smithy/core v3 circular dependency

@smithy/core v3.x introduced sub-path exports (/schema, /protocols, etc.)
with circular dependencies that break Jest 27's module system. When aws.js
is loaded (directly or via app.js), it initializes all 5 AWS SDK clients at
module level; any unmocked client triggers the cycle, leaving schema undefined
and crashing with "Cannot read properties of undefined (reading 'for')".

Fixes:
- Add __tests__/__mocks__/aws.js with jest.fn() stubs for all aws.js exports
- Endpoint tests: switch jest.mock("aws.js") to use factory pointing at the
  manual mock, preventing the real aws.js from loading
- AWS unit tests: add stub mocks for each AWS SDK client not under test so
  none of the real constructors run during module initialization
- app.test.js, error.test.js: mock aws.js since they load it via app.js
- package.json: add testPathIgnorePatterns to exclude __mocks__/ from test
  discovery

Generated with Claude Sonnet 4.6 (claude-sonnet-4-6) via Claude Code
Framework: Jest 27 (babel-jest)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jermnelson

__tests__/__mocks__/aws.js

@@ -0,0 +1,15 @@
+const requestMarc = jest.fn()
+const hasMarc = jest.fn()
+const getMarc = jest.fn()
+const listGroups = jest.fn()
+const buildAndSendSqsMessage = jest.fn()
+const detectLanguage = jest.fn()
+
+module.exports = {
+  requestMarc,
+  hasMarc,
+  getMarc,
+  listGroups,
+  buildAndSendSqsMessage,
+  detectLanguage,
+}

__tests__/app.test.js

@@ -2,6 +2,7 @@ import request from "supertest"
 import app from "app.js"
 
 jest.mock("mongo.js")
+jest.mock("aws.js", () => require("./__mocks__/aws.js"))
 
 describe("GET /", () => {
   it("returns health check", async () => {

__tests__/aws.cognito.test.js

@@ -6,6 +6,10 @@ import {
 } from "@aws-sdk/client-cognito-identity-provider"
 import { listGroups } from "aws.js"
 
+jest.mock("@aws-sdk/client-sqs", () => ({ SQSClient: jest.fn() }))
+jest.mock("@aws-sdk/client-s3", () => ({ S3Client: jest.fn() }))
+jest.mock("@aws-sdk/client-lambda", () => ({ LambdaClient: jest.fn() }))
+jest.mock("@aws-sdk/client-comprehend", () => ({ ComprehendClient: jest.fn() }))
 jest.mock("@aws-sdk/client-cognito-identity-provider", () => {
   const mockCognitoIdentityProviderClient = jest.fn()
   const mockPaginateListGroups = jest.fn()

__tests__/aws.comprehend.test.js

@@ -5,6 +5,13 @@ import {
 } from "@aws-sdk/client-comprehend"
 import { detectLanguage } from "aws.js"
 
+jest.mock("@aws-sdk/client-cognito-identity-provider", () => ({
+  CognitoIdentityProviderClient: jest.fn(),
+  paginateListGroups: jest.fn(),
+}))
+jest.mock("@aws-sdk/client-sqs", () => ({ SQSClient: jest.fn() }))
+jest.mock("@aws-sdk/client-s3", () => ({ S3Client: jest.fn() }))
+jest.mock("@aws-sdk/client-lambda", () => ({ LambdaClient: jest.fn() }))
 jest.mock("@aws-sdk/client-comprehend", () => {
   const mockSend = jest.fn()
   return {

__tests__/aws.marc.test.js

@@ -11,6 +11,12 @@ import {
 import { requestMarc, hasMarc, getMarc } from "aws.js"
 import { Readable } from "stream"
 
+jest.mock("@aws-sdk/client-cognito-identity-provider", () => ({
+  CognitoIdentityProviderClient: jest.fn(),
+  paginateListGroups: jest.fn(),
+}))
+jest.mock("@aws-sdk/client-sqs", () => ({ SQSClient: jest.fn() }))
+jest.mock("@aws-sdk/client-comprehend", () => ({ ComprehendClient: jest.fn() }))
 jest.mock("@aws-sdk/client-s3", () => {
   const mockSend = jest.fn()
   return {

__tests__/aws.sqs.test.js

@@ -6,6 +6,13 @@ import {
 } from "@aws-sdk/client-sqs"
 import { buildAndSendSqsMessage } from "aws.js"
 
+jest.mock("@aws-sdk/client-cognito-identity-provider", () => ({
+  CognitoIdentityProviderClient: jest.fn(),
+  paginateListGroups: jest.fn(),
+}))
+jest.mock("@aws-sdk/client-s3", () => ({ S3Client: jest.fn() }))
+jest.mock("@aws-sdk/client-lambda", () => ({ LambdaClient: jest.fn() }))
+jest.mock("@aws-sdk/client-comprehend", () => ({ ComprehendClient: jest.fn() }))
 jest.mock("@aws-sdk/client-sqs", () => {
   const mockSend = jest.fn()
   return {

__tests__/endpoints/groups.test.js

@@ -2,7 +2,7 @@ import request from "supertest"
 import app from "app.js"
 import * as aws from "aws.js"
 
-jest.mock("aws.js")
+jest.mock("aws.js", () => require("../__mocks__/aws.js"))
 
 describe("GET /groups", () => {
   const groups = [

__tests__/endpoints/helpers.test.js

@@ -2,7 +2,7 @@ import request from "supertest"
 import app from "app.js"
 import * as aws from "aws.js"
 
-jest.mock("aws.js")
+jest.mock("aws.js", () => require("../__mocks__/aws.js"))
 jest.mock("jwt.js", () => {
   return {
     __esModule: true,

__tests__/endpoints/marcGet.test.js

@@ -2,7 +2,7 @@ import request from "supertest"
 import app from "app.js"
 import * as aws from "aws.js"
 
-jest.mock("aws.js")
+jest.mock("aws.js", () => require("../__mocks__/aws.js"))
 
 describe("GET /:resourceId/job/:username/:timestamp", () => {
   describe("MARC does not exist", () => {

__tests__/endpoints/marcPost.test.js

@@ -9,7 +9,7 @@ resource.timestamp = new Date(resource.timestamp)
 // Multiple files.
 
 jest.mock("mongo.js")
-jest.mock("aws.js")
+jest.mock("aws.js", () => require("../__mocks__/aws.js"))
 jest.mock("jwt.js", () => {
   return {
     __esModule: true,