feat(settings): add a Compact buttons appearance toggle (#1189)

* feat(ui): prototype compact hero and toolbar buttons (Large/Small appearance setting)

* feat(settings): rename action-button size toggle to "Compact buttons"

Promote the hero-button prototype to a real, app-wide setting.

- rename heroButtonSize → buttonSize, data-hero-buttons → data-button-size,
  hero-action-bar/hero-btn-label → compact-action-bar/compact-btn-label
- relabel "Hero buttons" → "Compact buttons" and broaden the description
  (action + toolbar buttons across detail pages and browse views) in all 11 locales
- move the feature CSS out of cover-lightbox.css into its own compact-buttons.css
- add tests: themeStore buttonSize toggle, SelectionToggleButton

* docs(changelog): compact buttons appearance toggle (#1189)

* docs(credits): compact buttons appearance toggle (#1189)

src/store/themeStore.ts

@@ -43,6 +43,9 @@ interface ThemeState {
   setEnablePlaylistCoverPhoto: (v: boolean) => void;
   showBitrate: boolean;
   setShowBitrate: (v: boolean) => void;
+  /** Compact (icon-only) vs. large action/toolbar buttons across detail pages and browse views. */
+  buttonSize: 'large' | 'small';
+  setButtonSize: (v: 'large' | 'small') => void;
   showRemainingTime: boolean;
   setShowRemainingTime: (v: boolean) => void;
   expandReplayGain: boolean;
@@ -102,6 +105,8 @@ export const useThemeStore = create<ThemeState>()(
       setEnablePlaylistCoverPhoto: (v) => set({ enablePlaylistCoverPhoto: v }),
       showBitrate: true,
       setShowBitrate: (v) => set({ showBitrate: v }),
+      buttonSize: 'large',
+      setButtonSize: (v) => set({ buttonSize: v }),
       showRemainingTime: false,
       setShowRemainingTime: (v) => set({ showRemainingTime: v }),
       expandReplayGain: false,