More webapp changes+fixes

webapp/src/app/features/channels/channel-detail/channel-detail.component.ts

@@ -390,4 +390,33 @@ export class ChannelDetailComponent implements OnInit {
       }
     });
   }
+
+  isUserSubscribed(): boolean {
+    return this.channel()?.subscription !== null;
+  }
+
+  toggleSelfSubscription(): void {
+    const channel = this.channel();
+    const userId = this.authService.getUserId();
+    if (!channel || !userId) return;
+
+    if (this.isUserSubscribed()) {
+      // Unsubscribe
+      const subscriptionId = channel.subscription!.subscription_id;
+      this.apiService.deleteSubscription(userId, subscriptionId).subscribe({
+        next: () => {
+          this.notification.success('Unsubscribed from channel');
+          this.loadChannel(channel.channel_id);
+        }
+      });
+    } else {
+      // Subscribe
+      this.apiService.createSubscription(userId, { channel_id: channel.channel_id }).subscribe({
+        next: () => {
+          this.notification.success('Subscribed to channel');
+          this.loadChannel(channel.channel_id);
+        }
+      });
+    }
+  }
 }