docs: request LLM model disclosure in PRs

- Add a lightweight AI assistance field to the pull request template

- Ask contributors to list materially used models without requiring prompts or automated enforcement

.github/PULL_REQUEST_TEMPLATE.md

@@ -10,6 +10,12 @@ Before opening a PR, read `CONTRIBUTING.md` and `AGENTS.md`. PRs should explain
 
 - Add a concise summary here.
 
+### AI assistance
+
+<!-- If an LLM materially helped create or modify this PR, list the model names. Otherwise write “None”. No prompts or transcripts are required. -->
+
+Models: None
+
 ### Validation
 
 - [ ] `bun run check`

CONTRIBUTING.md

@@ -35,6 +35,7 @@ Pull requests must be reviewable without guessing the author's intent.
 - Explain what changed and why it changed.
 - Include a concrete list or paragraph of meaningful changes.
 - Document validation, such as `bun run check`, targeted tests, docs-only review, or an explicit reason validation was not run.
+- Complete the AI assistance section. If an LLM materially helped create or modify the PR, list the model names you know. Write `None` otherwise. This is review context, not authorship attribution; prompts and transcripts are not required.
 - Keep the body primarily in English. Code identifiers, file paths, logs, error messages, and short quoted examples may use their original language.
 
 ### Reviewability