refactor(组件): 优化tabbar的z-index值并调整客服按钮的导航方式

将tabbar的z-index值从999999调整为999，避免过高层级导致不必要的覆盖问题。同时，将客服按钮的导航方式从使用open-type="contact"改为直接使用`$utils.navigateTo`跳转，提升代码可维护性。

components/base/tabbar.vue

@@ -80,7 +80,7 @@
 			flex-direction: row;
 			height: 120rpx;
 			padding-bottom: env(safe-area-inset-bottom);
-			z-index: 999999;
+			z-index: 999;
 			bottom: 0;
 			left: 0;
 			color: #CCCCCC;

pages/index/center.vue

@@ -71,14 +71,22 @@
 					<text>激活码</text>
 				</view>
 
-				<button open-type="contact" class="share">
+				<!-- <button open-type="contact" class="share">
 					<view class="tool">
 						<view class="tool-icon tool-icon-bg">
 							<uv-icon name="server-fill" color="#05d9a2" size="56rpx" />
 						</view>
 						<text>联系客服</text>
 					</view>
-				</button>
+				</button> -->
+				
+				<view class="tool" @click="$utils.navigateTo('/pages_order/mine/service')">
+					<view class="tool-icon tool-icon-bg">
+						<uv-icon name="server-fill" color="#05d9a2" size="56rpx" />
+					</view>
+					<text>联系客服</text>
+				</view>
+				
 				<view class="tool" @click="$refs.configPopup.open('user_ys')">
 					<view class="tool-icon tool-icon-bg">
 						<uv-icon name="question-circle" color="#05d9a2" size="56rpx" />
@@ -136,9 +144,9 @@
 			</view>
 		</view>
 
-		<view class="service" @click="$utils.navigateTo('/pages_order/mine/service')">
+		<!-- <view class="service" @click="$utils.navigateTo('/pages_order/mine/service')">
 			<image src="@/pages_order/static/center/service.png" mode=""></image>
-		</view>
+		</view> -->
 
 		<popupActivate ref="popupActivate"></popupActivate>
 		<popupSharing ref="popupSharing"></popupSharing>