flask guides import-html; retention docstring

CHANGELOG.md

@@ -22,6 +22,19 @@ ADR-007 and ADR-002.
   tables; in self-hosted mode one stored loan expands into a take and a return,
   so a returned drive is distinguishable from one still out.
 
+- **`flask guides import-html` - an existing HTML article becomes a guide.**
+  A site adopting this app arrives holding procedures already written: styled
+  HTML pages that get mailed around and opened off a share. Retyping one into
+  the editor is how a good procedure stays on a share forever. The importer
+  reads the page and produces blocks - steps, callouts, code, checklists,
+  tables, lists - and lifts embedded images into `guideimages` so a 1.6 MB
+  document stops carrying its screenshots as base64. Imports land as DRAFTS,
+  and `--dry-run` (the default) reports what it would produce without writing.
+  Conversion is deliberately lossy: colour, fonts and layout go, because that
+  is the whole reason a guide is stored as blocks rather than markup. The
+  blocks go through the same validator the editor uses, so an import cannot
+  store something the editor could not have produced.
+
 ### Fixed
 
 - **Every report offers to email itself, not just two of them.** `POST