fix(web): 来源小字按消息角色区分语义——用户'来自',她'发送至'

- SourceLabel 加 role: user 消息显示'来自 <deviceId>'(她收到,来自主人端), assistant 消息显示'发送至 <deviceId>'(她回复到的端)
- 修复: 之前她发的消息也标'来自 web:chrome:...' 语义错误,不是她来自用户设备
- 4 处调用点传 message.role; 前端 build 绿

frontend/web/src/components/chat.tsx

@@ -120,11 +120,14 @@ function statusLabel(status: ToolStatus): string {
  *  concrete client the message came from, e.g. "来自 web:chrome:a1b2c3". Rendered
  *  only when a deviceId is present, so legacy/unlabelled messages stay clean. The
  *  Web client defaults to this label; other clients decide themselves. */
-function SourceLabel({ deviceId }: { deviceId?: string }): React.ReactNode {
+function SourceLabel({ deviceId, role }: { deviceId?: string; role?: string }): React.ReactNode {
   if (!deviceId) return null;
+  // A user message is received FROM a client; an assistant reply goes TO the
+  // client that prompted it. Semantic direction differs — "来自" vs "发送至".
+  const dir = role === "assistant" ? "发送至" : "来自";
   return (
     <div className="text-[10px] leading-tight text-[var(--mu-text-lo)]">
-      来自 {deviceId}
+      {dir} {deviceId}
     </div>
   );
 }
@@ -213,7 +216,7 @@ function AssistantParaBubble({
         {full && message.mood ? (
           <div className="mb-1 text-xs text-[var(--mu-text-lo)]">心情 · {message.mood}</div>
         ) : null}
-        {full ? <SourceLabel deviceId={message.deviceId} /> : null}
+        {full ? <SourceLabel deviceId={message.deviceId} role={message.role} /> : null}
         {full ? <WakePath active={active} /> : null}
         {full ? <ThinkingBlock text={message.thinking} streaming={message.streaming} /> : null}
         {full ? message.tools?.map((t, i) => <ToolCard key={i} tool={t} />) : null}
@@ -245,7 +248,7 @@ function UserParaBubble({
         ) : null}
         <span className="whitespace-pre-wrap">{renderContent(text)}</span>
       </div>
-      {full ? <SourceLabel deviceId={message.deviceId} /> : null}
+      {full ? <SourceLabel deviceId={message.deviceId} role={message.role} /> : null}
     </div>
   );
 }
@@ -319,7 +322,7 @@ function UserBubble({ message, mode }: { message: ChatMessage; mode: Mode }): Re
         ) : null}
         {body}
       </div>
-      <SourceLabel deviceId={message.deviceId} />
+      <SourceLabel deviceId={message.deviceId} role={message.role} />
       <SenderLabel name={message.senderName} />
     </div>
   );
@@ -345,7 +348,7 @@ function AssistantBubble({
         {message.mood ? (
           <div className="mb-1 text-xs text-[var(--mu-text-lo)]">心情 · {message.mood}</div>
         ) : null}
-        <SourceLabel deviceId={message.deviceId} />
+        <SourceLabel deviceId={message.deviceId} role={message.role} />
         <WakePath active={active} />
         <ThinkingBlock text={message.thinking} streaming={message.streaming} />
         {message.tools?.map((t, i) => <ToolCard key={i} tool={t} />)}