feat: add customer service chat, optimize case and homepage, fix api proxy

这一提交完成了多项功能升级与优化：
1.  新增全局浮动客服组件，集成腾讯云TRTC聊天能力并添加错误格式化工具
2.  新增图片资源并调整部分静态文件结构
3.  优化案例页面：重构筛选逻辑、新增空状态处理、添加加载更多功能
4.  优化首页布局：修复统计数字动画、调整移动端适配样式、优化轮播逻辑
5.  重构官方内容获取工具：添加缓存机制、优化媒体资源处理
6.  优化API代理配置，移除默认本地代理并新增环境变量配置
7.  新增页面数据恢复刷新逻辑，优化页面交互体验
8.  修复按钮组件冗余代码，调整头部导航移动端样式

components/CustomerChatFloating.vue

@@ -0,0 +1,151 @@
+<script setup>
+const route = useRoute()
+const isOpen = ref(false)
+const context = ref({ title: '在线客服', source: '' })
+
+const isInteriorPage = computed(() => route.path !== '/')
+
+function openFloatingChat() {
+  context.value = {
+    title: '在线客服',
+    source: isInteriorPage.value ? '' : ''
+  }
+  isOpen.value = true
+}
+
+function closeChat() {
+  isOpen.value = false
+}
+
+function onKeydown(event) {
+  if (event.key === 'Escape' && isOpen.value) closeChat()
+}
+
+onMounted(() => window.addEventListener('keydown', onKeydown))
+onBeforeUnmount(() => window.removeEventListener('keydown', onKeydown))
+</script>
+
+<template>
+  <Teleport to="body">
+    <Transition name="consult-float">
+      <button
+        v-if="!isOpen"
+        class="consult-float-button"
+        :class="{ 'is-interior': isInteriorPage }"
+        type="button"
+        aria-label="打开在线客服"
+        title="在线客服"
+        @click="openFloatingChat"
+      >
+        <AppIcon name="service" />
+        <span>客服</span>
+      </button>
+    </Transition>
+
+    <Transition name="consult-panel">
+      <div v-if="isOpen" class="consult-chat-shell" :class="{ 'is-interior': isInteriorPage }">
+        <ClientOnly>
+          <ChatOfficialChatWindow :context="context" @close="closeChat" />
+          <template #fallback>
+            <section class="consult-client-loading">
+              <strong>正在打开在线客服...</strong>
+            </section>
+          </template>
+        </ClientOnly>
+      </div>
+    </Transition>
+  </Teleport>
+</template>
+
+<style scoped>
+.consult-float-button {
+  position: fixed;
+  z-index: 46;
+  right: clamp(18px, 2.7vw, 12px);
+  bottom: clamp(18px, 25vw, 520px);
+  min-width: 88px;
+  height: 48px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  padding: 0 16px;
+  border: 1px solid rgba(255, 255, 255, 0.28);
+  border-radius: 999px;
+  color: #fff;
+  background: var(--gradient-action);
+  box-shadow: 0 16px 34px rgba(35, 111, 231, 0.26);
+  font-size: 14px;
+  font-weight: 600;
+  transition:
+    transform 0.2s,
+    box-shadow 0.2s,
+    opacity 0.2s;
+}
+
+.consult-float-button :deep(.app-icon) {
+  width: 20px;
+  height: 20px;
+}
+.consult-float-button:hover {
+  transform: translateY(-3px);
+  box-shadow: 0 20px 40px rgba(35, 111, 231, 0.34);
+}
+.consult-float-button:active {
+  transform: translateY(1px) scale(0.98);
+}
+.consult-chat-shell {
+  position: fixed;
+  z-index: 90;
+  right: clamp(16px, 2.4vw, 36px);
+  bottom: clamp(16px, 2.4vw, 36px);
+}
+.consult-chat-shell.is-interior {
+  bottom: calc(clamp(16px, 2.4vw, 36px) + 58px);
+}
+.consult-client-loading {
+  width: min(420px, calc(100vw - 32px));
+  height: 180px;
+  display: grid;
+  place-items: center;
+  border-radius: 12px;
+  color: #2f4056;
+  background: #fff;
+  box-shadow: 0 24px 64px rgba(37, 94, 160, 0.18);
+}
+.consult-float-enter-active,
+.consult-float-leave-active,
+.consult-panel-enter-active,
+.consult-panel-leave-active {
+  transition:
+    opacity 0.2s,
+    transform 0.24s cubic-bezier(0.22, 1, 0.36, 1);
+}
+.consult-float-enter-from,
+.consult-float-leave-to {
+  opacity: 0;
+  transform: translateY(12px) scale(0.96);
+}
+.consult-panel-enter-from,
+.consult-panel-leave-to {
+  opacity: 0;
+  transform: translateY(16px) scale(0.98);
+}
+@media (max-width: 640px) {
+  .consult-float-button {
+    right: 16px;
+    bottom: 16px;
+    min-width: 80px;
+    height: 44px;
+  }
+  .consult-float-button.is-interior {
+    bottom: 70px;
+  }
+  .consult-chat-shell,
+  .consult-chat-shell.is-interior {
+    right: 0;
+    bottom: 0;
+    left: 0;
+  }
+}
+</style>