chore: media compression feature groundwork

docs/design/states.md

@@ -325,3 +325,18 @@ Added by the Media screens, none of which exist yet:
 | Retention | `/settings` | Default (90 days or 5 GB), age only, size only (Forever), shortening (confirm), save error |
 
 401 is global. The 403 on `/activity` has local copy because the page itself is refused; the 403 on the summary or export of a non-admin is never shown, since the controls are hidden.
+
+## Added with Image variants
+
+Every state is drawn on `source/RenewCMS Screens Image variants.dc.html` and listed with its trigger and copy in [image-variants](screens/image-variants.md), which also holds the states matrix and the back-office error copy (400, 401, 403, 404, 409, 413, 422, 500).
+
+| Screen | Route | States |
+|---|---|---|
+| Variants list | `/settings/media/variants` | Loaded, loading, empty (two templates), error, forbidden, row menu, row action in progress, purge confirm, delete confirm, delete in progress, request reference |
+| Add / edit variant | slide-over (desktop), full page (mobile) | Create pristine and dirty, field errors, no dimension, name taken (409), saving, save error, edit pristine and dirty, unsaved changes, PNG without quality |
+| Media library | `/media` | Grid with badges, sort menu, filter With variants, filter Without, nothing to show, delete confirm with variants |
+| Image detail | `/media` (panel) | Partly generated, nothing generated, generating, generation failed, no variants defined, SVG source, animated GIF source, preview dialog |
+| Cache | `/settings/media/cache` | Loaded, loading, empty, purging, purge done, purge failed, error, purge all (confirm, typed), purge unused |
+| Editor picker | `/article/:id/edit` | Variant select, select open, no variants defined, variant deleted, variant disabled |
+
+The public request contract (200, 400 `unknown_variant` or `unsupported_parameter`, 404) is not a screen; it is section 7 of the same file.