feat: 系统配置 + 用户签名

- 新增 sys_config 表，存储应用版本号、标语、描述
- 关于小菜弹窗版本号改为从数据库动态获取
- 用户表新增 slogan 字段（个性签名）
- 编辑资料页面支持修改签名
- 管理后台新增系统配置管理页面
- 更新 CLAUDE.md 文档

client/src/pages/profile/index.vue

@@ -12,7 +12,7 @@
       </view>
       <view class="p-info">
         <text class="p-name">{{ userStore.nickname }}</text>
-        <text class="p-tagline">记账小能手</text>
+        <text class="p-tagline">{{ userStore.slogan }}</text>
         <text class="p-streak">累计 {{ txStore.total }} 笔记录</text>
       </view>
       <Icon name="chevronRight" :size="28" color="rgba(255,255,255,0.6)" />
@@ -85,9 +85,9 @@
     <view class="modal-mask" v-if="showAbout" @tap="showAbout = false">
       <view class="modal" @tap.stop>
         <text class="about-title">小菜记账</text>
-        <text class="about-version">v1.0.0</text>
-        <text class="about-desc">温暖 x 轻松的个人记账小程序</text>
-        <text class="about-desc">让记账从负担变成享受</text>
+        <text class="about-version">v{{ appConfig.app_version || '1.0.0' }}</text>
+        <text class="about-desc">{{ appConfig.app_slogan || '温暖 x 轻松的个人记账小程序' }}</text>
+        <text class="about-desc">{{ appConfig.app_description || '让记账从负担变成享受' }}</text>
         <view class="modal-btns modal-btns-top">
           <view class="modal-btn confirm" @tap="showAbout = false">知道了</view>
         </view>
@@ -143,6 +143,7 @@ import { useUserStore } from '@/stores/user'
 import { useGroupStore } from '@/stores/group'
 import { waitForReady } from '@/utils/app-ready'
 import { getTransactions } from '@/api/transaction'
+import { getConfig } from '@/api/config'
 import { formatAmount } from '@/utils/format'
 import { statusBarHeight } from '@/utils/system'
 import Icon from '@/components/Icon/Icon.vue'
@@ -159,6 +160,7 @@ const loading = ref(true)
 const showAbout = ref(false)
 const showIdentity = ref(false)
 const initialLoaded = ref(false)
+const appConfig = ref<Record<string, string>>({})
 
 onMounted(async () => {
   await waitForReady()
@@ -169,7 +171,8 @@ onMounted(async () => {
       budgetStore.fetchBudget(),
       txStore.fetchTransactions({ page: 1, pageSize: 1 }),
       userStore.fetchUserInfo(),
-      groupStore.fetchGroups()
+      groupStore.fetchGroups(),
+      getConfig().then(config => { appConfig.value = config }).catch(() => {})
     ])
   } catch (e) {
     console.error('Profile load error:', e)