Cosmos cassandra conversion instructions

[TheovanKraay]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• My contribution adds a new instruction, prompt, or chat mode file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, or chat mode with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.

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Description

Instructions file for converting Cassandra applications to using Azure Cosmos DB (with Spring Data Cosmos module).

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Type of Contribution

• New instruction file.
• New prompt file.
• New chat mode file.
• New collection file.
• Update to existing instruction, prompt, chat mode, or collection.
• Other (please specify):

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Additional Notes

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

[Copilot]

Pull request overview

This PR adds a comprehensive instruction file for converting Spring Boot applications from Apache Cassandra to Azure Cosmos DB using Spring Data Cosmos. The guide is based on real-world conversion experience and provides detailed step-by-step instructions covering dependency updates, configuration changes, entity conversion, repository updates, and troubleshooting.

Key Changes

• New instruction file: convert-cassandra-to-spring-data-cosmos.instructions.md (1,114 lines) providing detailed conversion guidance
• README update: Added entry in the instructions table for the new file with appropriate install badges

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
instructions/convert-cassandra-to-spring-data-cosmos.instructions.md	Comprehensive 11-step guide covering Cassandra to Cosmos DB conversion, including dependency management, entity/repository conversion, authentication setup, and troubleshooting for 10+ common issues
docs/README.instructions.md	Added table entry for the new instruction file with VS Code and VS Code Insiders install links

[aaronpowell]

Copilot has noted some things that might be some typing mistakes or copy/paste errors @TheovanKraay - can you review them and apply (or close) as relevant.

[TheovanKraay]

@aaronpowell all good suggestions, commited.

[TheovanKraay]

@aaronpowell is this ok to merge?