fix(mobile): highlight new-chat button and flex-center composer labels

- AskSourceHeader: solid brand-red new-chat button, flex-centered label
- replace padding+line-height centering with flex on chips, hold-talk,
  send, bubble-action, transcript-toggle, system-text, scope-note
- carries the in-flight AskSourceHeader extraction on sop/web-ai pages
  (parallel session work; its test updates intentionally left uncommitted)

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

@@ -0,0 +1,156 @@
+<template>
+  <view class="ask-source-head">
+    <view class="head-row">
+      <text class="head-title">问 · 数字师傅</text>
+      <view class="head-actions">
+        <text class="head-context">{{ context }}</text>
+        <button class="new-chat-button" :disabled="loading" @click="emit('newConversation')">新对话</button>
+      </view>
+    </view>
+    <view class="source-switch" aria-label="问答来源">
+      <button
+        class="source-option"
+        :class="{ active: active === 'assistant' }"
+        :aria-current="active === 'assistant' ? 'page' : undefined"
+        @click="selectAssistant"
+      >
+        工作助手
+      </button>
+      <button
+        class="source-option"
+        :class="{ active: active === 'web' }"
+        :aria-current="active === 'web' ? 'page' : undefined"
+        @click="selectWeb"
+      >
+        查全网
+      </button>
+    </view>
+  </view>
+</template>
+
+<script setup lang="ts">
+const props = withDefaults(defineProps<{
+  active: 'assistant' | 'web';
+  context: string;
+  loading?: boolean;
+}>(), {
+  loading: false
+});
+
+const emit = defineEmits<{
+  selectAssistant: [];
+  selectWeb: [];
+  newConversation: [];
+}>();
+
+const selectAssistant = () => {
+  if (props.active !== 'assistant') emit('selectAssistant');
+};
+
+const selectWeb = () => {
+  if (props.active !== 'web') emit('selectWeb');
+};
+</script>
+
+<style scoped>
+.ask-source-head {
+  flex-shrink: 0;
+  padding: 8px 12px 6px;
+  border-bottom: 1px solid #ebedf0;
+  background: #ffffff;
+}
+
+.head-row {
+  display: flex;
+  min-height: 44px;
+  align-items: center;
+  justify-content: space-between;
+  gap: 8px;
+  margin-bottom: 6px;
+}
+
+.head-title {
+  flex-shrink: 0;
+  color: #18202b;
+  font-size: 16px;
+  font-weight: 800;
+}
+
+.head-actions {
+  display: flex;
+  min-width: 0;
+  align-items: center;
+  justify-content: flex-end;
+  gap: 6px;
+}
+
+.head-context {
+  min-width: 0;
+  overflow: hidden;
+  color: #7b8492;
+  font-size: 12px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.new-chat-button {
+  flex-shrink: 0;
+  display: flex;
+  min-height: 44px;
+  align-items: center;
+  justify-content: center;
+  margin: 0;
+  padding: 0 14px;
+  border: 1px solid var(--employee-primary, #e60012);
+  border-radius: 999px;
+  background: var(--employee-primary, #e60012);
+  color: #ffffff;
+  font-size: 12px;
+  font-weight: 600;
+  line-height: 1;
+}
+
+.new-chat-button[disabled] {
+  opacity: 0.6;
+}
+
+.new-chat-button::after,
+.source-option::after {
+  border: none;
+}
+
+.source-switch {
+  display: flex;
+  gap: 0;
+  margin: 0;
+  padding: 3px;
+  border-radius: 999px;
+  background: #f2f3f5;
+}
+
+.source-option {
+  display: flex;
+  flex: 1;
+  box-sizing: border-box;
+  height: 44px;
+  min-height: 44px;
+  align-items: center;
+  justify-content: center;
+  margin: 0;
+  padding: 0;
+  border: none;
+  border-radius: 999px;
+  background: transparent;
+  color: #5a6270;
+  font-size: 13px;
+  font-weight: 500;
+  line-height: 1.2;
+}
+
+.source-option.active {
+  background: #ffffff;
+  color: #c8001a;
+  font-weight: 700;
+  box-shadow: 0 1px 4px rgba(20, 24, 31, 0.08);
+}
+</style>

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

@@ -271,14 +271,18 @@ defineExpose({ teardown, setDraft });
 
 .chip {
   flex-shrink: 0;
+  display: flex;
+  min-height: 30px;
+  align-items: center;
+  justify-content: center;
   margin: 0;
-  padding: 5px 12px;
+  padding: 0 13px;
   border: 1px solid #f0c0c5;
   border-radius: 999px;
   background: #ffffff;
   color: #c8001a;
   font-size: 13px;
-  line-height: 1.4;
+  line-height: 1;
 }
 
 .media-chip {
@@ -359,7 +363,6 @@ defineExpose({ teardown, setDraft });
   color: #232a33;
   font-size: 16px;
   font-weight: 600;
-  line-height: 1.2;
   user-select: none;
   -webkit-user-select: none;
 }
@@ -397,7 +400,6 @@ defineExpose({ teardown, setDraft });
   color: #ffffff;
   font-size: 15px;
   font-weight: 600;
-  line-height: 1.2;
 }
 
 .composer-panel {