Add AI Contribution Policy to CONTRIBUTING.md

CONTRIBUTING.md

@@ -4,6 +4,7 @@
 
 - [Contribution Guidelines](#contribution-guidelines)
   - [Introduction](#introduction)
+  - [AI Contribution Policy](#ai-contribution-policy)
   - [Issues](#issues)
     - [How to report issues](#how-to-report-issues)
     - [Types of issues](#types-of-issues)
@@ -67,6 +68,17 @@ Sensitive security-related issues should be reported to [security@gitea.io](mail
 
 For configuring IDEs for Gitea development, see the [contributed IDE configurations](contrib/ide/).
 
+## AI Contribution Policy
+
+Contributions made with the assistance of AI tools are welcome, but contributors must use them responsibly.
+
+1. Before prompting, search for open issues or previous pull requests and include links to them issues in the prompt.
+2. Review AI-generated code closely before submitting a pull request.
+4. Manually test the changes and add appropriate automated tests where feasible.
+3. Only use AI to assist in contributions that you understand well enough to respond to feedback without relying on AI.
+
+Maintainers reserve the right to close pull requests and issues that appear to be low-quality AI-generated content. We welcome new contributors, but cannot sustain the effort of supporting contributors who primarily defer to AI rather than engaging substantively with the review process.
+
 ## Issues
 
 ### How to report issues