chore: update Blueprint Mode to v38 with improved model and description

[mubaidr]

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 node update-readme.js and verified that README.md is up to date.

---

Description

---

Type of Contribution

• New instruction file.
• New prompt file.
• New chat mode file.
• Other (please specify): Updated tool usage policy

---

Additional Notes

---

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

Updates the Blueprint Mode chat mode from v37 to v38 with refined model specification and enhanced description. The changes focus on improving the model reference and strengthening the description to better convey the mode's capabilities.

• Updated model specification from "GPT-4.1" to "GPT-5 mini (copilot)"
• Enhanced description with more specific language about tool usage policy and validation
• Added continuous validation requirement and clarification on accuracy principles

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
chatmodes/blueprint-mode.chatmode.md	Updated version, model, description, and added continuous validation guidelines
README.chatmodes.md	Updated table entry to reflect v38 title and new description