feat(theme): R10 S1 — semantic status colors (danger/warn/success)

Add theme-scoped --danger/--warn/--success (+ -fg) tokens wired into the v4
@theme inline, replacing ~110 raw red/amber/emerald/green palette refs across
34 files. Fixes light-theme contrast failures (fixed Tailwind shades fell to
~1.7-3:1 on white). Status colors are scheme-independent — recognised by hue,
shifting only by theme to hold contrast (bright on dark bg, darkened on light).
Solid fills use the paired -fg text; @source inline guarantees the full -fg set
exists. IMDb rating gold kept as a deliberate decorative non-status exception.

frontend/src/components/ui/DraftSaveBar.tsx

@@ -47,12 +47,12 @@ export function DraftSaveBar({
     <div data-testid="draft-save-bar" className={wrap}>
       <span data-testid="draft-save-status" data-state={state} className="text-sm text-muted">
         {state === "saved" ? (
-          <span className="text-emerald-500 inline-flex items-center gap-1.5">
+          <span className="text-success inline-flex items-center gap-1.5">
             <Check className="w-4 h-4" />
             {labels.saved}
           </span>
         ) : state === "error" ? (
-          <span className="text-red-500">{labels.failed}</span>
+          <span className="text-danger">{labels.failed}</span>
         ) : (
           labels.unsaved
         )}