feat(titlebar): theme-colored window bar on macOS (#1199)

* feat(titlebar): theme-colored window bar on macOS

macOS showed the grey native title bar that ignores the app theme
(#1198). Enable titleBarStyle: Overlay so the webview reaches the top
edge and the native traffic lights float over the existing in-page
title bar, which already paints with the active theme.

Reuses the Linux title-bar grid: the bar is shown on macOS too (hidden
in native fullscreen), without the custom window buttons since the
traffic lights stay native. The GTK resize grips are now Linux-only.
Renamed the stylesheet to drop the misleading linux-only name.

* docs(changelog): macOS themed title bar

* fix(titlebar): crisp macOS bar text — drop transform layer and shadow

* fix(titlebar): drop now-playing text from the macOS bar

src/config/settingsCredits.ts

@@ -392,6 +392,7 @@ const CONTRIBUTOR_ENTRIES = [
       'Compact buttons — appearance toggle that switches action and toolbar buttons to icon-only across detail headers and browse views, app-wide (PR #1189)',
       'Playlist sort — sort a playlist by date added (newest/oldest) or any track column from a visible sort dropdown (PR #1191)',
       'Configurable artist backdrops — per-place source order + on/off (mainstage hero, artist page, fullscreen), with the mainstage hero showing the artist backdrop and prefetching upcoming ones (PR #1193)',
+      'Themed window title bar on macOS — follows the active theme instead of the grey system bar, with the native window buttons floating over it (PR #1199)',
     ],
   },
   {