Add pull request template with accessibility checklist

Author: pauljadam

.github/pull_request_template.md

@@ -0,0 +1,17 @@
+## Description
+<!-- Describe your changes -->
+
+## Accessibility Checklist
+Before submitting, ensure:
+- [ ] All images have accessibility labels or are marked as hidden
+- [ ] All interactive elements have clear, descriptive labels
+- [ ] Color is not the only means of conveying information
+- [ ] Custom controls have appropriate accessibility traits
+- [ ] Tested with VoiceOver (if UI changes)
+- [ ] No generic labels like "Button" or "Image"
+
+## Testing
+<!-- How did you test these changes? -->
+
+## Screenshots
+<!-- If applicable, add screenshots -->