feat: add spring-notes sample app integrated with Keploy

[Pratham0320]

Description

This pull request adds a new Java Spring Boot sample app (spring-notes) demonstrating how to integrate Keploy for test generation. The app includes simple in-memory CRUD endpoints and includes setup instructions to run Keploy via Docker on Windows.

Fixes keploy#115

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Ran mvn spring-boot:run to start the server locally.
• Tested APIs using curl and Postman:
  • POST /notes to add notes
  • GET /notes to retrieve all
  • GET /notes/{id} to fetch by ID
• Keploy was run using Docker (due to OS constraints on Windows):

  docker run --rm --name keploy `
    -v ${PWD}:/app `
    -p 16789:16789 `
    -e KEPLOY_MODE=record `
    -e KEPLOY_APP_NAME=spring-notes `
    -e KEPLOY_COMMAND="mvn spring-boot:run" `
    ghcr.io/keploy/keploy
  
  

My code follows the style guidelines of this project

I have performed a self-review of my own code

I have commented my code, particularly in hard-to-understand areas

I have made corresponding changes to the documentation

My changes generate no new warnings

I have added tests that prove my fix is effective or that my feature works (via Keploy)

New and existing unit tests pass locally with my changes

Any dependent changes have been merged and published in downstream modules

I have checked my code and corrected any misspellings

I have tagged the reviewers in a comment below incase my pull request is ready for a review

I have signed the commit message to agree to Developer Certificate of Origin (DCO) (to certify that I wrote or otherwise have the right to submit your contribution to the project.) by adding "--signoff" to my git commit command.

@Pratham0320 this PR is ready for review.