chore: migrate to new GitHub issue template workflow

[DrWheelicus]

Description

Replace the old single ISSUE_TEMPLATE.md with the new YAML-based issue forms workflow under .github/ISSUE_TEMPLATE/. This adds structured form templates for bug reports, feature requests, and questions, giving users a better experience when filing issues.

Type of Change

• Refactor

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• My changes generate no new warnings

How Has This Been Tested?

• Open a new issue and verify the template chooser appears
• Confirm each template (Bug Report, Feature Request, Question) renders correctly as a form
• Confirm blank issues can still be created

Additional Context

Migrates from the legacy single-file issue template to GitHub's newer issue forms (YAML-based), which provide structured form fields with validation, placeholders, and labels.