Refactor integration tests and remove legacy test script

[adity1raut]

Summary

A short description of what this PR changes and why.

• Replace the legacy Bash test script (test/test.sh) with a comprehensive TypeScript integration test suite (src/test/integration.test.ts) using Mocha and Supertest
• Fix Docker build by updating .dockerignore to allow test/data and correcting the COPY path in the Dockerfile from data to test/data
• Add new test dependencies (mocha, supertest, @types/*) and npm scripts for running integration tests
• Updated the integration test script to use supertest and Mocha for improved testing capabilities.
• Added new integration tests for various applications including nodejs-base-app, python-base-app, and others.
• Removed the old test.sh script to streamline the testing process.
• Enhanced the package.json to include necessary dependencies for testing.
• Implemented readiness checks and deployment verification in the new test structure.

Related issue

• Fixed Implement tests from .sh to .ts with supertest #77

Type of change

• Bug fix
• New feature
• Documentation
• Chore / CI
• Breaking change

How to test

Steps to reproduce or verify the change locally:

1. Checkout the branch
2. Run npm ci (or equivalent)
3. Run npm test and any additional verification steps

Checklist

• I have read the contributing guidelines
• I added tests that prove my fix is effective or that my feature works
• I updated documentation if necessary

Notes for reviewers

Any additional context for the reviewer, design decisions, or tradeoffs.

Release notes

Short note for changelog/release, if applicable.