Create Cosmos DB DataModeling prompt.md

[sesmyrnov]

Pull Request Checklist

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

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Description

This pull request adding new Cosmos DB Data Modeling prompt which is used as a Step-by-step guide for capturing key application requirements for NoSQL use-case and access patterns requirements and documenting them in the cosmosdb_requirements.md file and then Design a Cosmos DB NoSQL model using the Core Philosophy and Design Patterns from this document, saving to the cosmosdb_data_model.md file

Type of Contribution

• New instruction file.
• [ x] New prompt file.
• New chat mode file.
• Other (please specify):

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Additional Notes

this was tested in GHC Agent mode with multiple models (Claude Sonnet is recommended)

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 Azure Cosmos DB NoSQL data modeling expert system prompt designed to guide users through the process of designing optimal Cosmos DB data models. The prompt provides a structured approach for capturing application requirements and access patterns, then generates two deliverable files: cosmosdb_requirements.md and cosmosdb_data_model.md.

Key changes include:

• Addition of a detailed prompt file with extensive guidance on Cosmos DB design patterns and best practices
• Integration of the new prompt into the README with proper formatting and installation links
• Comprehensive coverage of aggregate-oriented design, partition key selection, and cost optimization strategies

Reviewed Changes

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

File	Description
prompts/cosmosdb-datamodeling.prompt.md	New comprehensive prompt file providing step-by-step guidance for Azure Cosmos DB NoSQL data modeling with extensive design patterns and best practices
README.prompts.md	Updated to include the new Cosmos DB data modeling prompt with proper installation links and description