docs: add pre-merge checklist to AGENTS.md

- Run pytest locally before pushing
- Run /review for code quality and QA validation
- Verify CI passes on Forgejo
- Address review comments before merging

AGENTS.md

@@ -112,3 +112,9 @@ forgejo_ci:
     test_failure:
       symptom: "FAILED test_name"
       fix: "Run failing test locally with pytest -xvs"
+
+pre_merge_checklist:
+  - run `pytest tests/ -v --tb=short` locally and ensure all new/changed tests pass
+  - run `/review` to get implementation review and QA validation
+  - verify CI passes on Forgejo (lint, test, type-check, build, deploy)
+  - address all review comments before merging to main