Align AI Usage section in PR template with Lightning (#1252)

Update the AI disclosure checkboxes to match Lightning's simplified
format (Claude Code / other model / not used) instead of the older
granular categories.

Author: elias-ba

.github/pull_request_template.md

@@ -14,17 +14,15 @@ List any considerations/cases/advice for testing/QA here.
 
 ## AI Usage
 
-Please disclose how you've used AI in this work (it's cool, we just want to know!):
-
-- [ ] Code generation (copilot but not intellisense)
-- [ ] Learning or fact checking
-- [ ] Strategy / design
-- [ ] Optimisation / refactoring
-- [ ] Translation / spellchecking / doc gen
-- [ ] Other
+Please disclose whether you've used AI anywhere in this PR (it's cool, we just
+want to know!):
+
+- [ ] I have used Claude Code
+- [ ] I have used another model
 - [ ] I have not used AI
 
-You can read more details in our [Responsible AI Policy](https://www.openfn.org/ai#pull-request-templates)
+You can read more details in our
+[Responsible AI Policy](https://www.openfn.org/ai#pull-request-templates)
 
 ## Release branch checklist