feat: 移动端工作计划/商机跟单/要客拜访支持编辑和删除

- 三个表单均支持 create+edit 双模式（通过 route.params.id 判断）
- 编辑模式: 加载已有数据 → 修改 → PUT 更新
- 编辑模式增加删除按钮
- 列表页卡片点击跳转编辑页
- 新增 6 条编辑路由

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

frontend/src/router/index.ts

@@ -39,8 +39,11 @@ const router = createRouter({
         { path: 'visit/new', name: 'VisitForm', component: () => import('@/views/mobile/VisitForm.vue') },
         { path: 'visit/:id/edit', name: 'VisitEdit', component: () => import('@/views/mobile/VisitForm.vue') },
         { path: 'work-plan/new', name: 'WorkPlanForm', component: () => import('@/views/mobile/WorkPlanForm.vue') },
+        { path: 'work-plan/:id/edit', name: 'WorkPlanEdit', component: () => import('@/views/mobile/WorkPlanForm.vue') },
         { path: 'mini-biz/new', name: 'MiniBusinessForm', component: () => import('@/views/mobile/MiniBusinessForm.vue') },
+        { path: 'mini-biz/:id/edit', name: 'MiniBusinessEdit', component: () => import('@/views/mobile/MiniBusinessForm.vue') },
         { path: 'key-visit/new', name: 'KeyVisitForm', component: () => import('@/views/mobile/KeyVisitForm.vue') },
+        { path: 'key-visit/:id/edit', name: 'KeyVisitEdit', component: () => import('@/views/mobile/KeyVisitForm.vue') },
         { path: 'note/new', name: 'DailyNoteForm', component: () => import('@/views/mobile/DailyNoteForm.vue') },
         { path: 'note/:id/edit', name: 'DailyNoteEdit', component: () => import('@/views/mobile/DailyNoteForm.vue') },
         { path: 'plans', name: 'PlansList', component: () => import('@/views/mobile/PlansList.vue') },