feat(media): align visual checks and variant UI with merged design

features/image_variants_screens.qa.md

@@ -54,7 +54,7 @@ Mock navigator.clipboard. No test freezes the system date (this screen shows no
     recompute; deleting the last row shows Empty; failures 404 (reloads the list) / 500 -> toast.
 14. **Reference card** — the 4 rows with badge words and icons, the exact JSON block text, the note;
     absent in Loading/Empty/Error/Forbidden; one column below 640.
-15. **Slide-over open/close** — desktop slide-over vs mobile full page (back arrow, no x), titles
+15. **Slide-over open/close** — desktop slide-over vs mobile bottom sheet (grabber, x; full-page back arrow superseded by features/variants_visual_conformance.feature), titles
     "Add variant" / "Edit variant: hero", focus on Name, pristine close without dialog, dirty close
     via Cancel/x/back/Escape opens "Discard changes?" with the right text, Keep editing / Discard
     changes behaviours, focus return to the opener.
@@ -135,7 +135,7 @@ Preview sample: north-wall.jpg, 4032 × 3024, 3.9 MB.
       `minmax(0,1.1fr) 104px 76px 72px 68px 92px 92px 132px 44px`, 36 px header, 48 px rows; cards 12 px
       padding with the name+switch line, the spec line, then count+menu; slide-over 960 px with a
       440 px form column; compare box 3:2, chips 8 px from the top corners, handle 32 px (44 px on
-      mobile) centred on a 2 px divider; footer 64 px (72 px on mobile).
+      mobile) centred on a 2 px divider; footer 64 px (mobile sheet footer: see features/variants_visual_conformance.feature).
 - [ ] Not drawn, no visual state: toggle failures, the purge/delete failure toasts, the 409-free
       status toasts, the 422 mapping, the clipboard states "Copied" (add only if the board draws it: it
       does not, so Vitest only), singular footer.