fix(mobile): precise centering in ask page switch and composer

Replace line-height centering with flex + fixed heights, and swap
emoji/unicode glyphs (＋ × ⌨ 🎤) for uni-icons vector icons so
alignment and rendering are consistent across platforms.

mobile-uni/src/components/chat/ChatComposer.vue

@@ -22,7 +22,7 @@
 
     <view class="composer-bar">
       <button class="composer-icon" :disabled="disabled || recording" aria-label="更多功能" @click="panelOpen = !panelOpen">
-        <text class="composer-icon-text">{{ panelOpen ? '×' : '＋' }}</text>
+        <uni-icons :type="panelOpen ? 'close' : 'plus'" size="20" color="#3a4350" />
       </button>
 
       <button
@@ -55,7 +55,7 @@
         :aria-label="voiceMode ? '切换键盘输入' : '切换语音输入'"
         @click="toggleVoiceMode"
       >
-        <text class="composer-icon-text">{{ voiceMode ? '⌨' : '🎤' }}</text>
+        <uni-icons :type="voiceMode ? 'compose' : 'mic'" size="19" color="#3a4350" />
       </button>
 
       <button
@@ -309,16 +309,19 @@ defineExpose({ teardown, setDraft });
 }
 
 .media-chip-remove {
+  display: flex;
   flex-shrink: 0;
   width: 24px;
   height: 24px;
+  align-items: center;
+  justify-content: center;
   margin: 0;
   padding: 0;
   border-radius: 50%;
   background: #eef0f3;
   color: #6b7480;
   font-size: 15px;
-  line-height: 24px;
+  line-height: 1;
 }
 
 .composer-bar {
@@ -328,32 +331,35 @@ defineExpose({ teardown, setDraft });
 }
 
 .composer-icon {
+  display: flex;
   flex-shrink: 0;
   width: 38px;
   height: 38px;
+  align-items: center;
+  justify-content: center;
   margin: 0;
   padding: 0;
   border: 1px solid #dfe3e8;
   border-radius: 50%;
   background: #ffffff;
-  line-height: 36px;
-}
-
-.composer-icon-text {
-  color: #3a4350;
-  font-size: 19px;
+  line-height: 1;
 }
 
 .hold-talk {
+  display: flex;
   flex: 1;
-  min-height: 38px;
+  height: 38px;
+  align-items: center;
+  justify-content: center;
   margin: 0;
+  padding: 0;
   border: 1px solid #dfe3e8;
   border-radius: 10px;
   background: #ffffff;
   color: #232a33;
   font-size: 16px;
   font-weight: 600;
+  line-height: 1.2;
   user-select: none;
   -webkit-user-select: none;
 }
@@ -379,8 +385,11 @@ defineExpose({ teardown, setDraft });
 }
 
 .composer-send {
+  display: flex;
   flex-shrink: 0;
-  min-height: 38px;
+  height: 38px;
+  align-items: center;
+  justify-content: center;
   margin: 0;
   padding: 0 16px;
   border-radius: 10px;
@@ -388,6 +397,7 @@ defineExpose({ teardown, setDraft });
   color: #ffffff;
   font-size: 15px;
   font-weight: 600;
+  line-height: 1.2;
 }
 
 .composer-panel {

mobile-uni/src/pages/user/sop/index.vue

@@ -2013,15 +2013,20 @@ onUnload(() => {
 }
 
 .chat-source-switch .source-option {
+  display: flex;
   flex: 1;
+  align-items: center;
+  justify-content: center;
+  box-sizing: border-box;
+  height: 32px;
   margin: 0;
-  padding: 6px 0;
+  padding: 0;
   border: none;
   border-radius: 999px;
   background: transparent;
   color: #5a6270;
   font-size: 14px;
-  line-height: 1.3;
+  line-height: 1.2;
 }
 
 .chat-source-switch .source-option.active {
@@ -2403,7 +2408,7 @@ onUnload(() => {
 }
 
 .chat-source-switch .source-option {
-  padding: 5px 0;
+  height: 30px;
   font-size: 13px;
 }