refactor: 四端完成 Options API → script setup + vuex → pinia 迁移

- buyer(95) / seller(169) / im(53) / manager(280) 共 597 个组件全部从 Options API 转换为 <script setup>
- 四端 vuex 全部移除，状态管理统一迁移至 pinia 4（stores/ 目录）
- util.js 等基础设施去除 vm 首参依赖；全局属性（$Message/$filters 等）在 script 内改为具名导入
- 被外部 ref 访问的公共组件均已补齐 defineExpose（清单见各端 MIGRATION-VUE3.md）
- 各端 eslint 启用 vue/component-api-style 防止新代码回退 Options API
- 四端 yarn build 全部通过；迁移约定与注意事项已更新至各端 MIGRATION-VUE3.md

im/src/views/other/404.vue

@@ -16,39 +16,34 @@
     </div>
   </div>
 </template>
-<script>
+<script setup>
+import { ref, onBeforeUnmount } from 'vue'
+import { useRouter } from 'vue-router'
 import { SvgNotFount } from '@/core/icons'
 
-export default {
-  name: 'NotFoundPage',
-  components: {
-    SvgNotFount,
-  },
-  data() {
-    return {
-      second: 10,
-      setInterval: null,
-    }
-  },
-  created() {
-    this.setInterval = setInterval(() => {
-      this.second--
-      if (this.second == 0) {
-        clearInterval(this.setInterval)
-        this.toHome()
-      }
-    }, 1000)
-  },
-  beforeUnmount() {
-    clearInterval(this.setInterval)
-  },
-  methods: {
-    toHome() {
-      this.$router.push({
-        path: '/',
-      })
-    },
-  },
+defineOptions({ name: 'NotFoundPage' })
+
+const router = useRouter()
+
+const second = ref(10)
+let timer = null
+
+timer = setInterval(() => {
+  second.value--
+  if (second.value == 0) {
+    clearInterval(timer)
+    toHome()
+  }
+}, 1000)
+
+onBeforeUnmount(() => {
+  clearInterval(timer)
+})
+
+function toHome() {
+  router.push({
+    path: '/',
+  })
 }
 </script>
 <style lang="less" scoped>