feat: Introduce new core components for conversation and speech management

- Added ConversationManager for managing conversation history with configurable limits.
- Implemented InputQueue for serial processing of input items.
- Created SpeechManager for handling text-to-speech generation and streaming.
- Developed StreamProcessor for processing LLM streams and forwarding events.
- Added TranscriptionManager for audio transcription using AI SDK.
- Introduced WebSocketManager for managing WebSocket connections and messaging.
- Updated VoiceAgent to support new architecture and improved socket handling.
- Refactored index files to export new core components.

dist/VoiceAgent.d.ts

@@ -20,6 +20,25 @@ export interface VoiceAgentOptions {
     /** Maximum audio input size in bytes (default: 10 MB) */
     maxAudioInputSize?: number;
 }
+/**
+ * A single-session voice agent that manages one WebSocket connection at a time.
+ *
+ * **Important:** Each `VoiceAgent` instance holds its own conversation history,
+ * input queue, speech state, and WebSocket. It is designed for **one user per
+ * instance**. To support multiple concurrent users, create a separate
+ * `VoiceAgent` for each connection:
+ *
+ * ```ts
+ * wss.on("connection", (socket) => {
+ *   const agent = new VoiceAgent({ model, ... });
+ *   agent.handleSocket(socket);
+ *   agent.on("disconnected", () => agent.destroy());
+ * });
+ * ```
+ *
+ * Sharing a single instance across multiple users will cause conversation
+ * history cross-contamination, interleaved audio, and unpredictable behavior.
+ */
 export declare class VoiceAgent extends EventEmitter {
     private socket?;
     private tools;
@@ -120,6 +139,10 @@ export declare class VoiceAgent extends EventEmitter {
      * Attach an existing WebSocket (server-side usage).
      * Use this when a WS server accepts a connection and you want the
      * agent to handle messages on that socket.
+     *
+     * **Note:** Calling this while a socket is already attached will cleanly
+     * tear down the previous connection first. Each `VoiceAgent` instance
+     * supports only one socket at a time — create a new agent per user.
      */
     handleSocket(socket: WebSocket): void;
     /**