Add admin route tests and DynamoDB integration

[csecrestjr]

Summary

• refactor admin users route to scan DynamoDB table and mask passwords
• add error handling for admin routes
• add Jest tests for admin routes and configure Jest/Supertest

Testing

• npm test (fails: jest: not found)

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https://chatgpt.com/codex/tasks/task_e_689fe2e6b3ec832190d72cf6d2c81f46

[Copilot]

Pull Request Overview

This PR migrates the admin users route from Mongoose to DynamoDB and adds comprehensive Jest test coverage. The changes modernize the data access layer while implementing proper error handling for admin operations.

• Replaces Mongoose User model with DynamoDB scan operations for fetching users
• Adds error handling with try-catch blocks for both admin routes
• Introduces Jest testing framework with Supertest for API route testing

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
backend/routes/admin.js	Migrates users route to DynamoDB scan operation and adds error handling to both routes
backend/routes/tests/admin.test.js	Adds comprehensive Jest tests for admin routes with mocking
backend/package.json	Configures Jest test runner and adds testing dependencies

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