Adds feature support template

Clarifies feature PR expectations so proposals outline scope, design, validation, and checklist items up front

Author: LoserCheems

.github/PULL_REQUEST_TEMPLATE/feature_support.md

@@ -0,0 +1,32 @@
+---
+name: "Feature Support"
+about: "Add a new feature with clear scope and tests"
+title: "[FEATURE] "
+labels: ["feature"]
+
+---
+
+## Summary
+- What feature is being added and why?
+
+## Design
+- Outline the design or architecture and mention alternatives considered.
+
+## Changes
+- Describe new or changed public APIs, configuration, or CLI behaviour.
+
+## Implementation Notes
+- Highlight tricky parts or noteworthy implementation details.
+
+## Tests
+- List unit or integration tests you added or updated and how you validated them.
+
+## Documentation
+- Mention doc updates or examples that accompany this feature.
+
+## Checklist
+- [ ] Linked issue provided
+- [ ] API stabilized
+- [ ] Tests added or updated
+- [ ] Docs added or updated
+- [ ] No known performance regressions