Feat: Now-Playing serverseitig syncen + in Topbar verschieben

Backend:
- nowPlaying Map trackt aktuell gespielten Sound pro Guild
- SSE broadcast { type: 'nowplaying' } bei play und stop
- nowplaying im SSE-Snapshot für neue Clients
- playFilePath Helper broadcastet ebenfalls (Party Mode)

Frontend:
- SSE-Handler für nowplaying Events (sync über alle Clients)
- Now-Playing als Pill-Badge in der Topbar (rechts, neben Channel)
- Bottombar komplett entfernt
- Fade-in Animation und accent-farbige Pill
- --accent-rgb CSS Variable für alle Themes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/App.tsx

@@ -154,12 +154,20 @@ export default function App() {
           const g = selectedRef.current?.split(':')[0];
           if (g && typeof vols[g] === 'number') setVolume(vols[g]);
         } catch { }
+        try {
+          const np = msg?.nowplaying || {};
+          const g = selectedRef.current?.split(':')[0];
+          if (g && typeof np[g] === 'string') setLastPlayed(np[g]);
+        } catch { }
       } else if (msg?.type === 'channel') {
         const g = selectedRef.current?.split(':')[0];
         if (msg.guildId === g) setSelected(`${msg.guildId}:${msg.channelId}`);
       } else if (msg?.type === 'volume') {
         const g = selectedRef.current?.split(':')[0];
         if (msg.guildId === g && typeof msg.volume === 'number') setVolume(msg.volume);
+      } else if (msg?.type === 'nowplaying') {
+        const g = selectedRef.current?.split(':')[0];
+        if (msg.guildId === g) setLastPlayed(msg.name || '');
       }
     });
     return () => { try { unsub(); } catch { } };
@@ -362,6 +370,15 @@ export default function App() {
         </div>
 
         <div className="topbar-right">
+          {lastPlayed && (
+            <div className="now-playing">
+              <div className="np-waves active">
+                <div className="np-wave-bar" /><div className="np-wave-bar" />
+                <div className="np-wave-bar" /><div className="np-wave-bar" />
+              </div>
+              <span className="np-name">{lastPlayed}</span>
+            </div>
+          )}
           {selected && (
             <div className="connection">
               <span className="conn-dot" />
@@ -594,18 +611,6 @@ export default function App() {
         )}
       </main>
 
-      {/* ═══ BOTTOM BAR ═══ */}
-      <div className="bottombar">
-        <div className="now-playing">
-          <div className={`np-waves ${lastPlayed ? 'active' : ''}`}>
-            <div className="np-wave-bar" /><div className="np-wave-bar" />
-            <div className="np-wave-bar" /><div className="np-wave-bar" />
-          </div>
-          <span className="np-label">Spielt:</span>
-          <span className="np-name">{lastPlayed || '—'}</span>
-        </div>
-      </div>
-
       {/* ═══ CONTEXT MENU ═══ */}
       {ctxMenu && (
         <div