fix(mobile-next): 未读角标改为最小 18×18、白字 12、圆角 9 并去掉重阴影

仅改 unread_count_view.dart。默认尺寸 18，数字 12，圆角 9；删除三层 BoxShadow。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

mobile-next/openim_common/lib/src/widgets/unread_count_view.dart

@@ -1,12 +1,11 @@
 import 'package:flutter/material.dart';
-import 'package:flutter_screenutil/flutter_screenutil.dart';
 import 'package:openim_common/openim_common.dart';
 
 class UnreadCountView extends StatelessWidget {
   const UnreadCountView({
     Key? key,
     this.count = 0,
-    this.size = 13,
+    this.size = 18,
     this.margin,
   }) : super(key: key);
   final int count;
@@ -20,43 +19,25 @@ class UnreadCountView extends StatelessWidget {
       child: Container(
         alignment: Alignment.center,
         margin: margin,
-        padding: count > 99 ? EdgeInsets.symmetric(horizontal: 4.w) : null,
-        constraints: BoxConstraints(maxHeight: size, minWidth: size),
-        decoration: _decoration,
-        child: _text,
+        padding: count > 99 ? const EdgeInsets.symmetric(horizontal: 4) : null,
+        constraints: BoxConstraints(
+          minWidth: size,
+          minHeight: size,
+          maxHeight: size,
+        ),
+        decoration: BoxDecoration(
+          color: Styles.c_FF381F,
+          borderRadius: BorderRadius.circular(9),
+        ),
+        child: Text(
+          '${count > 99 ? '99+' : count}',
+          style: const TextStyle(
+            fontSize: 12,
+            color: Color(0xFFFFFFFF),
+          ),
+          textAlign: TextAlign.center,
+        ),
       ),
     );
   }
-
-  Text get _text => Text(
-        '${count > 99 ? '99+' : count}',
-        style: TextStyle(
-          fontSize: 8.sp,
-          color: const Color(0xFFFFFFFF),
-        ),
-        textAlign: TextAlign.center,
-      );
-
-  Decoration get _decoration => BoxDecoration(
-        color: Styles.c_FF381F,
-        shape: count > 99 ? BoxShape.rectangle : BoxShape.circle,
-        borderRadius: count > 99 ? BorderRadius.circular(10.r) : null,
-        boxShadow: [
-          BoxShadow(
-            color: const Color(0x26C61B4A),
-            offset: Offset(1.15.w, 1.15.h),
-            blurRadius: 57.58.r,
-          ),
-          BoxShadow(
-            color: const Color(0x1AC61B4A),
-            offset: Offset(2.3.w, 2.3.h),
-            blurRadius: 11.52.r,
-          ),
-          BoxShadow(
-            color: const Color(0x0DC61B4A),
-            offset: Offset(4.61.w, 4.61.h),
-            blurRadius: 17.28.r,
-          ),
-        ],
-      );
 }