refactor(layout): 统一页面边距管理，移除 Container 限制

- layoutConfig.js: 新增 LAYOUT_PADDING 常量 { base: 4, md: 6, lg: '80px' }
- MainLayout.js: 在 Outlet 容器上统一应用 px={LAYOUT_PADDING.x}
- HomeNavbar.js: 边距从 lg:8 改为 lg:'80px'，与内容区对齐
- AppFooter.js: 移除 Container，边距改为 lg:'80px'

页面组件清理（移除冗余的 px/Container）：
- Company, Community, Center, Profile, Settings
- ValueForum, DataBrowser, LimitAnalyse, StockOverview, Concept

特殊处理：
- CompanyHeader: 使用负边距实现全宽背景
- Concept Hero: 使用负边距实现全宽背景

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/views/StockOverview/index.js

@@ -3,7 +3,6 @@ import { useNavigate } from 'react-router-dom';
 import { getApiBase } from '@utils/apiConfig';
 import {
   Box,
-  Container,
   Heading,
   Text,
   Input,
@@ -633,6 +632,7 @@ const StockOverview = () => {
         pt={{ base: 20, md: 24 }}
         pb={{ base: 16, md: 20 }}
         borderBottom={`1px solid rgba(139, 92, 246, 0.3)`}
+        borderRadius="xl"
         zIndex={1}
       >
         {/* 背景装饰 */}
@@ -648,7 +648,7 @@ const StockOverview = () => {
           filter="blur(60px)"
         />
         
-        <Container maxW="container.xl" position="relative">
+        <Box px={6} position="relative">
           <VStack spacing={8} align="center">
             <VStack spacing={4} textAlign="center" maxW="3xl">
               <HStack spacing={3}>
@@ -855,11 +855,11 @@ const StockOverview = () => {
               </Stat>
             </SimpleGrid>
           </VStack>
-        </Container>
+        </Box>
       </Box>
 
       {/* 主内容区 */}
-      <Container maxW="container.xl" py={10} position="relative" zIndex={1}>
+      <Box py={10} px={6} position="relative" zIndex={1}>
         {/* 日期选择器 */}
         <Box mb={6}>
           <Flex align="center" gap={4} flexWrap="wrap">
@@ -1195,7 +1195,7 @@ const StockOverview = () => {
             )}
           </Card>
         </Box>
-        </Container>
+        </Box>
 
         {/* 个股列表弹窗 */}
         <ConceptStocksModal