feat: 新增弹幕描边粗细设置，默认值降低

lib/pages/video/detail/widgets/header_control.dart

@@ -1,4 +1,5 @@
 import 'dart:io';
+import 'dart:math';
 
 import 'package:floating/floating.dart';
 import 'package:flutter/material.dart';
@@ -724,6 +725,8 @@ class _HeaderControlState extends State<HeaderControl> {
     double fontSizeVal = widget.controller!.fontSizeVal;
     // 弹幕速度
     double danmakuDurationVal = widget.controller!.danmakuDurationVal;
+    // 弹幕描边
+    double strokeWidth = widget.controller!.strokeWidth;
 
     final DanmakuController danmakuController =
         widget.controller!.danmakuController!;
@@ -857,6 +860,44 @@ class _HeaderControlState extends State<HeaderControl> {
                       ),
                     ),
                   ),
+                  Text('描边粗细 $strokeWidth'),
+                  Padding(
+                    padding: const EdgeInsets.only(
+                      top: 0,
+                      bottom: 6,
+                      left: 10,
+                      right: 10,
+                    ),
+                    child: SliderTheme(
+                      data: SliderThemeData(
+                        trackShape: MSliderTrackShape(),
+                        thumbColor: Theme.of(context).colorScheme.primary,
+                        activeTrackColor: Theme.of(context).colorScheme.primary,
+                        trackHeight: 10,
+                        thumbShape: const RoundSliderThumbShape(
+                            enabledThumbRadius: 6.0),
+                      ),
+                      child: Slider(
+                        min: 0,
+                        max: 3,
+                        value: strokeWidth,
+                        divisions: 6,
+                        label: '$strokeWidth',
+                        onChanged: (double val) {
+                          strokeWidth = val;
+                          widget.controller!.strokeWidth = val;
+                          setState(() {});
+                          try {
+                            final DanmakuOption currentOption =
+                                danmakuController.option;
+                            final DanmakuOption updatedOption =
+                            currentOption.copyWith(strokeWidth: val);
+                            danmakuController.updateOption(updatedOption);
+                          } catch (_) {}
+                        },
+                      ),
+                    ),
+                  ),
                   Text('字体大小 ${(fontSizeVal * 100).toStringAsFixed(1)}%'),
                   Padding(
                     padding: const EdgeInsets.only(