fix: volume slider disappearing + theme overlapping favorites

- SSE handler now distinguishes per-guild events (single NowPlaying)
  from snapshots (Record<string, NowPlaying>) to prevent state corruption
- Theme selector moved left (right: 72px) to not overlap favorites button

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

web/src/plugins/radio/RadioTab.tsx

@@ -100,7 +100,20 @@ export default function RadioTab({ data }: { data: any }) {
 
   // ── Handle SSE data ──
   useEffect(() => {
-    if (data?.playing) setNowPlaying(data.playing);
+    if (data?.guildId && 'playing' in data) {
+      // Per-guild SSE event (broadcastState): playing is single NowPlaying | null
+      setNowPlaying(prev => {
+        if (data.playing) {
+          return { ...prev, [data.guildId]: data.playing };
+        }
+        const next = { ...prev };
+        delete next[data.guildId];
+        return next;
+      });
+    } else if (data?.playing) {
+      // Snapshot: playing is Record<string, NowPlaying>
+      setNowPlaying(data.playing);
+    }
     if (data?.favorites) setFavorites(data.favorites);
     // Volume from snapshot or radio_volume event
     if (data?.volumes && selectedGuild && data.volumes[selectedGuild] != null) {

web/src/styles.css

@@ -972,7 +972,7 @@ html, body {
 .radio-theme {
   position: absolute;
   top: 16px;
-  right: 16px;
+  right: 72px;
   z-index: 25;
   display: flex;
   align-items: center;