Feature: Watch Together - History, Titel-Fetch, Next-Button

Server:
- Video-History Tracking (max 50 Einträge pro Raum)
- History wird bei Skip und Play-Video gespeichert
- Server-seitiger Titel-Fetch via noembed.com als Fallback

Client:
- Aufklappbare History-Sektion im Queue-Panel
- "Weiter" Button mit Text-Label statt nur Icon
- YouTube-Thumbnails in der Warteschlange
- History in RoomState integriert

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

web/src/plugins/watch-together/watch-together.css

@@ -779,3 +779,92 @@
     display: none;
   }
 }
+
+/* ── History Section ── */
+.wt-history-section {
+  border-top: 1px solid var(--bg-tertiary);
+  margin-top: 8px;
+  padding-top: 8px;
+}
+
+.wt-history-toggle {
+  width: 100%;
+  background: none;
+  border: none;
+  color: var(--text-muted);
+  font-size: 13px;
+  cursor: pointer;
+  padding: 6px 8px;
+  text-align: left;
+  border-radius: var(--radius);
+  transition: background var(--transition), color var(--transition);
+}
+.wt-history-toggle:hover {
+  background: var(--bg-tertiary);
+  color: var(--text-normal);
+}
+
+.wt-history-list {
+  max-height: 200px;
+  overflow-y: auto;
+  margin-top: 4px;
+}
+
+.wt-history-item {
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+  padding: 8px 10px;
+  border-radius: var(--radius);
+  opacity: 0.6;
+  transition: opacity var(--transition), background var(--transition);
+}
+.wt-history-item:hover {
+  opacity: 1;
+  background: var(--bg-tertiary);
+}
+
+.wt-history-item-title {
+  font-size: 13px;
+  color: var(--text-muted);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.wt-history-item-by {
+  font-size: 11px;
+  color: var(--text-faint);
+}
+
+/* ── Queue Thumbnail ── */
+.wt-queue-item-info {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  min-width: 0;
+  flex: 1;
+}
+
+.wt-queue-thumb {
+  width: 48px;
+  height: 36px;
+  object-fit: cover;
+  border-radius: 4px;
+  flex-shrink: 0;
+}
+
+.wt-queue-item-text {
+  min-width: 0;
+  flex: 1;
+}
+
+/* ── Next Button ── */
+.wt-next-btn {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+  font-size: 13px;
+  padding: 6px 12px;
+  white-space: nowrap;
+}