🎨 style: unify card header UI, switch to Avatar icons & remove oversized props

Summary
• Replaced gradient header blocks with compact, neutral headers wrapped in `Avatar` across the following pages:
  - Channel / EditChannel.js
  - Channel / EditTagModal.js
  - Redemption / EditRedemption.js
  - Token / EditToken.js
  - User / EditUser.js
  - User / AddUser.js

Details
1. Added `Avatar` import and substituted raw icon elements, assigning semantic colors (`blue`, `green`, `purple`, `orange`, etc.) and consistent 16 px icons for a cleaner look.
2. Removed gradient backgrounds, decorative “blur-ball” shapes, and extra paddings from header containers to achieve a tight, flat design.
3. Stripped all `size="large"` attributes from `Button`, `Input`, `Select`, `DatePicker`, `AutoComplete`, and `Avatar` components, allowing default sizing for better visual density.
4. Eliminated redundant `bodyStyle` background overrides in some `SideSheet` components.
5. No business logic touched; all changes are purely presentational.

Result
The editing and creation dialogs now share a unified, compact style consistent with the latest design language, improving readability and user experience without altering functionality.

web/src/pages/User/AddUser.js

@@ -8,7 +8,8 @@ import {
   Spin,
   Typography,
   Card,
-  Tag
+  Tag,
+  Avatar
 } from '@douyinfe/semi-ui';
 import {
   IconUser,
@@ -78,10 +79,7 @@ const AddUser = (props) => {
           borderBottom: '1px solid var(--semi-color-border)',
           padding: '24px'
         }}
-        bodyStyle={{
-          backgroundColor: 'var(--semi-color-bg-0)',
-          padding: '0'
-        }}
+        bodyStyle={{ padding: '0' }}
         visible={props.visible}
         width={isMobile() ? '100%' : 600}
         footer={
@@ -89,7 +87,6 @@ const AddUser = (props) => {
             <Space>
               <Button
                 theme="solid"
-                size="large"
                 className="!rounded-full"
                 onClick={submit}
                 icon={<IconSave />}
@@ -99,7 +96,6 @@ const AddUser = (props) => {
               </Button>
               <Button
                 theme="light"
-                size="large"
                 className="!rounded-full"
                 type="primary"
                 onClick={handleCancel}
@@ -116,20 +112,13 @@ const AddUser = (props) => {
         <Spin spinning={loading}>
           <div className="p-6">
             <Card className="!rounded-2xl shadow-sm border-0">
-              <div className="flex items-center mb-4 p-6 rounded-xl" style={{
-                background: 'linear-gradient(135deg, #1e3a8a 0%, #2563eb 50%, #3b82f6 100%)',
-                position: 'relative'
-              }}>
-                <div className="absolute inset-0 overflow-hidden">
-                  <div className="absolute -top-10 -right-10 w-40 h-40 bg-white opacity-5 rounded-full"></div>
-                  <div className="absolute -bottom-8 -left-8 w-24 h-24 bg-white opacity-10 rounded-full"></div>
-                </div>
-                <div className="w-10 h-10 rounded-full bg-white/20 flex items-center justify-center mr-4 relative">
-                  <IconUserAdd size="large" style={{ color: '#ffffff' }} />
-                </div>
-                <div className="relative">
-                  <Text style={{ color: '#ffffff' }} className="text-lg font-medium">{t('用户信息')}</Text>
-                  <div style={{ color: '#ffffff' }} className="text-sm opacity-80">{t('创建新用户账户')}</div>
+              <div className="flex items-center mb-2">
+                <Avatar size="small" color="blue" className="mr-2 shadow-md">
+                  <IconUserAdd size={16} />
+                </Avatar>
+                <div>
+                  <Text className="text-lg font-medium">{t('用户信息')}</Text>
+                  <div className="text-xs text-gray-600">{t('创建新用户账户')}</div>
                 </div>
               </div>
 
@@ -141,7 +130,6 @@ const AddUser = (props) => {
                     onChange={(value) => handleInputChange('username', value)}
                     value={username}
                     autoComplete="off"
-                    size="large"
                     className="!rounded-lg"
                     prefix={<IconUser />}
                     showClear
@@ -156,7 +144,6 @@ const AddUser = (props) => {
                     onChange={(value) => handleInputChange('display_name', value)}
                     value={display_name}
                     autoComplete="off"
-                    size="large"
                     className="!rounded-lg"
                     prefix={<IconUser />}
                     showClear
@@ -171,7 +158,6 @@ const AddUser = (props) => {
                     onChange={(value) => handleInputChange('password', value)}
                     value={password}
                     autoComplete="off"
-                    size="large"
                     className="!rounded-lg"
                     prefix={<IconKey />}
                     required
@@ -185,7 +171,6 @@ const AddUser = (props) => {
                     onChange={(value) => handleInputChange('remark', value)}
                     value={remark}
                     autoComplete="off"
-                    size="large"
                     className="!rounded-lg"
                     prefix={<IconEdit />}
                     showClear