Add prompt safety instruction and CI template

[cmendesvdl]

Summary

• Add the requested upstream AI prompt-engineering safety instruction under .github/instructions/ without changing its substantive guidance.
• Add the reusable CI/squash-auto-merge template documentation under Data/Templates/.

Validation

• The instruction was checked against the reviewed upstream snapshot; only one trailing space on its final comment line was removed to satisfy the repository whitespace gate.
• The embedded workflow YAML parses, and all seven embedded PowerShell scripts parse.
• The actual workflow has not been installed by this change.
• Required PowerShell and integrity validation check passes.

Please review the repo-wide applyTo: ['*'] scope and the guidance before merging.