fix(clip): a time's error line sits in the flow, the remove button off the cut, and every player surface rings amber

- useTimecodeField holds a time field's draft for its caller, which places TimecodeError (role
  alert) in its own flow under the fields' row: it no longer lies over the crop row taking its
  clicks, runs out of the editor's card, or joins the field's <label> name.
- The editor's remove-cut buttons sit in a row under the track at their cut (trackLeft), off the
  cut's grab area, where a press drags it; RangeTrack's adornment slot is gone.
- media-focus re-points --focus to the media amber on the Plex player, the YouTube stage and every
  bg-media-chrome surface; a contract test holds each such class string to media-focus or
  media-scope, the field's focus edge to the focus token, and --color-focus to the inline theme.
- An upload's quota headline says the converted file does not fit, not "Storage full".
- DESIGN.md: the tokens paragraph says what is re-pointed where; the decision row measures all
  three colours on the chrome.

frontend/src/components/ui/AnchoredPopover.tsx

@@ -104,7 +104,7 @@ export const ROVING_HIGHLIGHT =
   "data-active:bg-accent/35 data-active:text-fg data-active:ring-1 data-active:ring-inset data-active:ring-accent/60";
 const HIGHLIGHT_SELECTED =
   "data-active:bg-accent/35 data-active:text-fg data-active:ring-2 data-active:ring-inset data-active:ring-accent/80";
-// On the always-dark media chrome (a player's menus, `bg-media-chrome` under white text) the theme's
+// On the always-dark media chrome (a player's menus, `bg-media-chrome media-focus` under white text) the theme's
 // `text-fg` is dark in the light theme: the highlighted row would go dark-on-dark. White instead.
 const MEDIA_HIGHLIGHT =
   "data-active:bg-white/15 data-active:text-white data-active:ring-1 data-active:ring-inset data-active:ring-white/40";