feat: add AI disclosure requirements to contributing guidelines and issue templates

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,21 @@
+## Problem
+Part of #NNN
+<!-- PRs with no linked scope item will be questioned. -->
+
+What does this solve?
+
+## Approach
+Why this approach?
+
+## Testing
+Paste ACTUAL command output here. For UI changes, include screenshots or recordings.
+
+### AI Disclosure
+- Tool(s):
+- Model(s):
+- Involvement:
+- Adversarial review:
+
+## Checklist
+- [ ] I ran an adversarial AI review of the diff and summarized findings above.
+- [ ] I ran the repo verify commands: `make lint`, `cd web && pnpm run lint`, `cd web && pnpm run format:check`, and relevant `go test ./...`.