feat: disable native decorations on Linux, hide custom TitleBar for tiling WMs

On tiling window managers (Hyprland, Sway, i3, bspwm, AwesomeWM, Openbox, etc.)
     the window has no title bar at all — neither native nor custom. On stacking DEs
     (GNOME, KDE, XFCE) the custom TitleBar can be toggled in settings as before.

     Native decorations are disabled on all Linux at startup. The frontend checks
     is_tiling_wm() to decide whether to render the custom TitleBar:
     - DE (GNOME/KDE): custom TitleBar shown (user-toggleable in settings)
     - Tiling WM: no TitleBar at all, setting hidden from Settings page

     Detection is based on environment variables:
     - HYPRLAND_INSTANCE_SIGNATURE, SWAYSOCK, I3SOCK (direct compositor signatures)
     - XDG_CURRENT_DESKTOP check for known tiling WMs

     Changes:
     - Added is_tiling_wm_cmd() Tauri command for frontend detection
     - Native decorations disabled on all Linux at startup
     - TitleBar not rendered on tiling WMs
     - Custom TitleBar setting hidden in Settings for tiling WMs

src/App.tsx

@@ -78,6 +78,12 @@ function AppShell() {
   const { t } = useTranslation();
   const isMobile = useIsMobile();
   const [isWindowFullscreen, setIsWindowFullscreen] = useState(false);
+  const [isTilingWm, setIsTilingWm] = useState(false);
+
+  useEffect(() => {
+    if (!IS_LINUX) return;
+    invoke<boolean>('is_tiling_wm_cmd').then(setIsTilingWm).catch(() => {});
+  }, []);
 
   useEffect(() => {
     if (!IS_LINUX) return;
@@ -108,10 +114,12 @@ function AppShell() {
   const hasOfflineContent = Object.values(offlineAlbums).some(a => a.serverId === serverId);
 
   // Sync custom titlebar preference with native decorations on Linux
+  // On tiling WMs decorations are always off (no native title bar to replace).
   useEffect(() => {
     if (!IS_LINUX) return;
-    invoke('set_window_decorations', { enabled: !useCustomTitlebar }).catch(() => {});
-  }, [useCustomTitlebar]);
+    const enabled = isTilingWm ? false : !useCustomTitlebar;
+    invoke('set_window_decorations', { enabled }).catch(() => {});
+  }, [useCustomTitlebar, isTilingWm]);
 
   useEffect(() => {
     if (!isLoggedIn || !activeServerId) return;
@@ -288,14 +296,14 @@ function AppShell() {
       className="app-shell"
       data-mobile={isMobile || undefined}
       data-mobile-player={isMobilePlayer || undefined}
-      data-titlebar={(IS_LINUX && useCustomTitlebar && !isWindowFullscreen) || undefined}
+      data-titlebar={(IS_LINUX && useCustomTitlebar && !isWindowFullscreen && !isTilingWm) || undefined}
       style={{
         '--sidebar-width': isMobile ? '0px' : (isSidebarCollapsed ? '72px' : 'clamp(200px, 15vw, 220px)'),
         '--queue-width': isMobile ? '0px' : (isQueueVisible ? `${queueWidth}px` : '0px')
       } as React.CSSProperties}
       onContextMenu={e => e.preventDefault()}
     >
-      {IS_LINUX && useCustomTitlebar && !isWindowFullscreen && <TitleBar />}
+      {IS_LINUX && useCustomTitlebar && !isWindowFullscreen && !isTilingWm && <TitleBar />}
       {!isMobile && (
         <Sidebar
           isCollapsed={isSidebarCollapsed}

src/pages/Settings.tsx

@@ -202,6 +202,13 @@ export default function Settings() {
   const clearAllOffline = useOfflineStore(s => s.clearAll);
   const clearHotCacheDisk = useHotCacheStore(s => s.clearAllDisk);
   const hotCacheEntries = useHotCacheStore(s => s.entries);
+  const [isTilingWm, setIsTilingWm] = useState(false);
+
+  useEffect(() => {
+    if (!IS_LINUX) return;
+    invoke<boolean>('is_tiling_wm_cmd').then(setIsTilingWm).catch(() => {});
+  }, []);
+
   const hotCacheTrackCount = useMemo(() => {
     if (!serverId) return 0;
     const prefix = `${serverId}:`;
@@ -618,7 +625,7 @@ export default function Settings() {
                   <span className="toggle-track" />
                 </label>
               </div>
-              {IS_LINUX && (
+              {IS_LINUX && !isTilingWm && (
                 <>
                   <div className="settings-section-divider" />
                   <div className="settings-toggle-row">