Give each test its own temporary directory

[theinfosecguy]

Problem & Solution Overview

The unit and integration tests shared fixed output directories under the repo (.test-output, .test-output-*, .integration-output), so two concurrent runs (e.g. npm test alongside npm run test:coverage) could delete each other's files mid-test. Each test now creates a unique directory under the OS temp dir in beforeEach (fs.mkdtempSync) and removes only its own directory in afterEach.

Testing Done

npm test: 203 passing. npm test and npm run test:coverage run concurrently with both passing (exit 0, 203 each). No shared output directories remain under the repo.