Standardize PR template with emoji sections and issue types (#316)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: denelon

.github/ISSUE_TEMPLATE/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,22 @@
+## 📖 Description
+<!-- Describe what this PR changes, why, and any limitations. -->
+
+## 🔗 References
+<!-- Link related issues, PRs, or docs. Use "Resolves #1234" to auto-close. -->
+
+## 🔍 Validation
+<!-- How did you test? List manual steps or note automated test coverage. -->
+
+## ✅ Checklist
+<!-- Place an "x" between the brackets to check an item. e.g: [x] -->
+
+- [ ] Signed the [Contributor License Agreement](https://cla.opensource.microsoft.com)
+- [ ] Linked to an issue
+- [ ] Updated documentation (if applicable)
+- [ ] Updated [Copilot instructions](.github/copilot-instructions.md) (if build, architecture, or conventions changed)
+
+## 📋 Issue Type
+<!-- Select the type that best describes this PR -->
+- [ ] Bug fix
+- [ ] Feature
+- [ ] Task