indexing policy: add link to the code of conduct

policy/indexing.md

@@ -7,6 +7,8 @@ Our policy is based on two principles:
 
 Note that for purposes of this document, the term "author" does not necessarily mean the original author of a mod. It should be understood to include a maintainer, custodian, etc.
 
+All CKAN users, mod authors, and the CKAN team are part of the CKAN community and must comply with the [Code of Conduct](https://github.com/KSP-CKAN/.github/?tab=coc-ov-file#readme).
+
 ## Indexing
 
 The CKAN team will not add a mod to CKAN without the author's permission. Checking the "Add to CKAN" checkbox on SpaceDock is taken as a request to have the mod added to CKAN (unless the uploader is not the author, see below).