Unify web player controls and add volume control

frontend/lib/widgets/web_stream_player_stub.dart

@@ -2,11 +2,13 @@ import 'package:flutter/material.dart';
 
 class WebStreamPlayer extends StatelessWidget {
   final String streamUrl;
+  final double volume;
   final int? refreshToken;
 
   const WebStreamPlayer({
     super.key,
     required this.streamUrl,
+    required this.volume,
     this.refreshToken,
   });
 

frontend/lib/widgets/web_stream_player_web.dart

@@ -1,3 +1,5 @@
+// ignore_for_file: avoid_web_libraries_in_flutter, deprecated_member_use
+
 import 'dart:html' as html;
 import 'dart:ui_web' as ui_web;
 
@@ -5,11 +7,13 @@ import 'package:flutter/material.dart';
 
 class WebStreamPlayer extends StatefulWidget {
   final String streamUrl;
+  final double volume;
   final int? refreshToken;
 
   const WebStreamPlayer({
     super.key,
     required this.streamUrl,
+    required this.volume,
     this.refreshToken,
   });
 
@@ -19,6 +23,7 @@ class WebStreamPlayer extends StatefulWidget {
 
 class _WebStreamPlayerState extends State<WebStreamPlayer> {
   late final String _viewType;
+  html.IFrameElement? _iframe;
 
   @override
   void initState() {
@@ -29,15 +34,30 @@ class _WebStreamPlayerState extends State<WebStreamPlayer> {
     ui_web.platformViewRegistry.registerViewFactory(_viewType, (int viewId) {
       final iframe = html.IFrameElement()
         ..src =
-            'flv_player.html?v=$cacheBuster&src=${Uri.encodeComponent(widget.streamUrl)}'
+            'flv_player.html?v=$cacheBuster'
+            '&src=${Uri.encodeComponent(widget.streamUrl)}'
+            '&volume=${widget.volume}'
         ..style.border = '0'
         ..style.width = '100%'
         ..style.height = '100%'
+        ..style.pointerEvents = 'none'
         ..allow = 'autoplay; fullscreen';
+      _iframe = iframe;
       return iframe;
     });
   }
 
+  @override
+  void didUpdateWidget(covariant WebStreamPlayer oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.volume != widget.volume) {
+      _iframe?.contentWindow?.postMessage({
+        'type': 'setVolume',
+        'value': widget.volume,
+      }, '*');
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return HtmlElementView(viewType: _viewType);