fix: 移动端列表页移除 v-loading 遮罩，修复卡片点击无反应

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

frontend/src/views/mobile/KeyVisitsList.vue

@@ -41,7 +41,7 @@ async function handleDelete(id: string) {
 
     <button class="new-btn" @click="router.push('/m/key-visit/new')">+ 新建要客</button>
 
-    <div v-loading="loading" class="cards">
+    <div class="cards">
       <div v-if="items.length === 0 && !loading" class="empty-state"><div class="empty-glyph">—</div><p class="empty-text">暂不要客记录</p></div>
       <article v-for="item in items" :key="item.id" class="card" @click="router.push(`/m/key-visit/${item.id}/edit`)">
         <div class="card-accent" :style="{ background: urgencyColors[item.urgency_level] || '#5B7FA5' }"></div>

frontend/src/views/mobile/MiniBizList.vue

@@ -41,7 +41,7 @@ async function handleDelete(id: string) {
 
     <button class="new-btn" @click="router.push('/m/mini-biz/new')">+ 新建商机</button>
 
-    <div v-loading="loading" class="cards">
+    <div class="cards">
       <div v-if="items.length === 0 && !loading" class="empty-state"><div class="empty-glyph">—</div><p class="empty-text">暂无商机记录</p></div>
       <article v-for="item in items" :key="item.id" class="card" @click="router.push(`/m/mini-biz/${item.id}/edit`)">
         <div class="card-accent" :style="{ background: statusColors[item.status] || '#C4934A' }"></div>

frontend/src/views/mobile/PlansList.vue

@@ -39,7 +39,7 @@ async function handleDelete(id: string) {
 
     <button class="new-btn" @click="router.push('/m/work-plan/new')">+ 新建计划</button>
 
-    <div v-loading="loading" class="cards">
+    <div class="cards">
       <div v-if="items.length === 0 && !loading" class="empty-state"><div class="empty-glyph">—</div><p class="empty-text">暂无工作计划</p></div>
       <article v-for="item in items" :key="item.id" class="card" @click="router.push(`/m/work-plan/${item.id}/edit`)">
         <div class="card-accent" style="background:#4A6741"></div>