- modules/breakwater exports Render(markdown) and Purify(html): goldmark GFM
in its default safe mode (raw HTML stripped, unsafe links dropped), then a
named bluemonday policy built from NewPolicy, not the UGC preset
- the policy is the PHP golem15/forum HTMLPurifier config 1:1: the fixed
element list, a[href|rel|target], http/https/mailto only, rel=nofollow on
every link, target=_blank plus noopener on fully-qualified links
- tests cover the PHP ForumMarkdownRenderTest corpus, links per scheme,
blank input, the Purify allow-list and concurrent use; testable examples
feed the docs page snippets
- module README, root module table row, introduction.md Utilities row and
docs/services/markdown.md (which gate serves user content vs admin fields)
- go.mod and go.sum unchanged: bluemonday v1.0.27 and goldmark v1.8.6 were
already pinned
