add pull request template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,43 @@
+---
+name: Pull request
+about: Propose a change to NotAlterra
+title: ''
+labels: ''
+assignees: ''
+---
+
+> **I will not respond to PRs that do not include a clear description or
+> that introduce unnecessary complexity.** If you are fixing a bug, say
+> what bug and how it was reproduced. If you are adding a feature, explain
+> why it belongs in this tool and not in a fork.
+
+## Description
+
+What does this change do, and why is it needed?
+
+## Type of change
+
+- [ ] Bug fix
+- [ ] New feature
+- [ ] Refactor / code quality
+- [ ] Documentation
+- [ ] Build / CI
+- [ ] Other: ___________
+
+## Verification
+
+- [ ] `cargo test` passes (all tests, including integration)
+- [ ] `python3 tests/_check.py` passes (100% doc coverage)
+- [ ] `npm install -g @inspecode/check && check --cargo-extra-args="-- --nocapture"` passes (if applicable)
+- [ ] No new compiler warnings
+- [ ] CHANGELOG.md updated if the change is user-facing
+
+## Notes (optional)
+
+Any background context, design trade-offs, or areas that need careful
+review.
+
+---
+
+NotAlterra is maintained by a single person. PRs may take time to review.
+A polite ping after a week is fine. Please be patient.