fix(voice): upsert trascrizioni per item_id invece di append

Il server ora invia aggiornamenti incrementali del transcript con item_id.
Il client sostituisce il transcript esistente con lo stesso item_id
invece di aggiungere duplicati parziali, mostrando sempre il testo completo.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Gabry848

src/hooks/useVoiceChat.ts

@@ -31,6 +31,7 @@ export interface ServerStatus {
 export interface VoiceTranscript {
   role: 'user' | 'assistant';
   content: string;
+  item_id?: string;
 }
 
 /**
@@ -123,7 +124,7 @@ export function useVoiceChat() {
     onConnectionClose:      (...args) => websocketCallbacksRef.current.onConnectionClose?.(...args),
     onStatus:               (...args) => websocketCallbacksRef.current.onStatus?.(...args),
     onAudioChunk:           (...args) => websocketCallbacksRef.current.onAudioChunk?.(...args),
-    onTranscript:           (...args) => websocketCallbacksRef.current.onTranscript?.(...args),
+    onTranscript:           (role, content, itemId) => websocketCallbacksRef.current.onTranscript?.(role, content, itemId),
     onToolCall:             (...args) => websocketCallbacksRef.current.onToolCall?.(...args),
     onToolOutput:           (...args) => websocketCallbacksRef.current.onToolOutput?.(...args),
     onDone:                 (...args) => websocketCallbacksRef.current.onDone?.(...args),
@@ -443,9 +444,20 @@ export function useVoiceChat() {
       }
     },
 
-    onTranscript: (role: 'user' | 'assistant', content: string) => {
+    onTranscript: (role: 'user' | 'assistant', content: string, itemId?: string) => {
       if (!isMountedRef.current) return;
-      setTranscripts(prev => [...prev, { role, content }]);
+      setTranscripts(prev => {
+        if (itemId) {
+          const idx = prev.findLastIndex(t => t.item_id === itemId);
+          if (idx !== -1) {
+            // Aggiorna il transcript esistente con il testo più completo
+            const updated = [...prev];
+            updated[idx] = { role, content, item_id: itemId };
+            return updated;
+          }
+        }
+        return [...prev, { role, content, item_id: itemId }];
+      });
     },
 
     onToolCall: (toolName: string, args: string) => {

src/services/voiceBotService.ts

@@ -60,6 +60,7 @@ export interface VoiceAudioResponse {
 export interface VoiceTranscriptResponse {
   type: 'transcript';
   role: 'user' | 'assistant';
+  item_id?: string;
   content: string;
 }
 
@@ -111,7 +112,7 @@ export enum WebSocketAuthState {
 export interface VoiceChatCallbacks {
   onStatus?: (phase: VoiceServerPhase, message: string) => void | Promise<void>;
   onAudioChunk?: (audioData: string, chunkIndex: number) => void;
-  onTranscript?: (role: 'user' | 'assistant', content: string) => void;
+  onTranscript?: (role: 'user' | 'assistant', content: string, itemId?: string) => void;
   onToolCall?: (toolName: string, args: string) => void;
   onToolOutput?: (toolName: string, output: string) => void;
   onError?: (error: string) => void;
@@ -459,7 +460,7 @@ export class VoiceBotWebSocket {
    * Gestisce risposta di trascrizione
    */
   private handleTranscriptResponse(response: VoiceTranscriptResponse): void {
-    this.callbacks.onTranscript?.(response.role, response.content);
+    this.callbacks.onTranscript?.(response.role, response.content, response.item_id);
   }
 
   /**