fix(design): rating and live colour tokens, the player's menus over its notices, the info overlay on a light theme (E28)

- F16: --rating (theme-scoped gold, 4.5:1 on the page and its chip), --rating-media, --live/--live-fg,
  --media-chrome replace 14 palette literals; a lint rule refuses palette classes; the theme contract
  measures them.
- The Plex player's notices drew over its open settings/tracks popovers: notices z-base, popovers z-menu.
- The player's info overlay rendered theme tokens on its always-dark panel: on a light theme the score
  (2.6:1), collection years (3.2:1) and cast initials (1.05:1) were unreadable; onDark variants now.
- The lint-rule contract tests share one ESLint with a one-off warm-up (a cold first lint took 8 s,
  past vitest's 5 s).

frontend/src/components/plexViews.tsx

@@ -441,8 +441,8 @@ export function PlexShowView({
                     }
                     className={`inline-flex items-center gap-1 ${onFilter ? "min-h-6 cursor-pointer hover:text-accent touch-target" : "cursor-default"}`}
                   >
-                    {/* decorative rating gold — intentionally NOT a status token */}
-                    · <Star className="w-3.5 h-3.5 text-amber-400" fill="currentColor" />
+                    {/* the rating gold — its own token, not --warn: a score is not a warning */}
+                    · <Star className="w-3.5 h-3.5 text-rating" fill="currentColor" />
                     {score.toFixed(1)}
                   </Pressable>
                 );