Enhance text input processing and LLM interaction in the backend

- Refactor TextInputProcessor to handle immediate and silent text inputs, improving user experience during voice interactions.
- Introduce PassthroughLLMAssistantAggregator to manage LLM responses while preserving context for downstream TTS processing.
- Update event handling for text input and client readiness, ensuring timely updates to the conversation context.
- Modify run_pipeline to integrate new aggregators and streamline message handling, enhancing overall pipeline efficiency.
- Improve message ordering in useVoicePreview to ensure accurate display of chat messages based on timestamps.

frontend/src/hooks/use-voice-preview.ts

@@ -54,6 +54,11 @@ function errorMessage(error: unknown, fallback: string): string {
   return fallback;
 }
 
+function messageOrder(message: ChatMessage): number {
+  const timestamp = Date.parse(message.timestamp);
+  return Number.isNaN(timestamp) ? Number.MAX_SAFE_INTEGER : timestamp;
+}
+
 function microphoneErrorMessage(error: unknown): string {
   if (error instanceof DOMException) {
     if (error.name === "NotAllowedError") {
@@ -137,6 +142,7 @@ export function useVoicePreview(assistantId: string | null) {
     const channel = dataChannelRef.current;
     dataChannelRef.current = null;
     if (channel) {
+      channel.onopen = null;
       channel.onmessage = null;
       channel.close();
     }
@@ -290,6 +296,9 @@ export function useVoicePreview(assistantId: string | null) {
       // 由浏览器侧主动创建,后端 SmallWebRTCConnection 的 on("datachannel") 会接住。
       const channel = pc.createDataChannel("chat");
       dataChannelRef.current = channel;
+      channel.onopen = () => {
+        channel.send(JSON.stringify({ type: "client-ready" }));
+      };
       channel.onmessage = (event) => {
         try {
           const msg = JSON.parse(event.data);
@@ -309,7 +318,14 @@ export function useVoicePreview(assistantId: string | null) {
                   ? msg.timestamp
                   : new Date().toISOString(),
             };
-            setMessages((prev) => [...prev, next]);
+            setMessages((prev) =>
+              [...prev, next].sort(
+                (a, b) =>
+                  messageOrder(a) - messageOrder(b) ||
+                  Number(a.id.replace("msg-", "")) -
+                    Number(b.id.replace("msg-", "")),
+              ),
+            );
           }
         } catch {
           /* 非 JSON / 未知消息,忽略 */