feat(stream): single-account Go-Live — broadcast on the conversation's session

Proven approach: the conversation (hear+speak) runs on @discordjs/voice; the
Go-Live broadcast is a SEPARATE stream connection created on the SAME selfbot
session (exactly like a real Discord client), so ONE account hears, speaks, AND
broadcasts — no second login, no self_deaf, no voice conflict.

- voice.ts captures its own voice session_id (adapter wrap) and exposes
  getSharedSession() {client, guildId, channelId, sessionId, botId}.
- broadcast.ts threads it into the StreamContext.
- selfbot.ts: when a shared session is present, build the Streamer on the
  conversation client and create the stream on its session_id (no login/joinVoice/
  humanPause); teardown only stops the stream (never leaves voice/destroys the
  shared client). Falls back to the dedicated-account path otherwise.

Verified live: Go-Live connected in ~7s while the conversation voice stayed
ready, and the broadcast was visible in Discord — all on one account.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

bot/src/voice.ts

@@ -86,12 +86,32 @@ export class VoiceSession {
   /** Apply a broadcast directive the brain requested (start/stop the stream). */
   onBroadcastAction?: (action: "start" | "stop") => void | Promise<void>;
 
+  /** The selfbot client behind this voice connection + the negotiated voice
+   *  session_id, so the broadcast (Go-Live) can ride the SAME session — one
+   *  account hears/speaks AND broadcasts. */
+  private readonly client: any;
+  private readonly channelId: string;
+  private sessionId?: string;
+
   constructor(channel: VoiceBasedChannel) {
     this.guildId = channel.guild.id;
+    this.channelId = channel.id;
+    this.client = (channel as any).client;
+    // Wrap the gateway adapter to capture our own voice session_id (needed to
+    // create the Go-Live stream on this same session).
+    const realCreator = channel.guild.voiceAdapterCreator;
+    const adapterCreator: typeof realCreator = (methods) =>
+      realCreator({
+        ...methods,
+        onVoiceStateUpdate: (d: any) => {
+          if (d?.session_id) this.sessionId = d.session_id;
+          return methods.onVoiceStateUpdate(d);
+        },
+      });
     this.connection = joinVoiceChannel({
       channelId: channel.id,
       guildId: channel.guild.id,
-      adapterCreator: channel.guild.voiceAdapterCreator,
+      adapterCreator,
       selfDeaf: false, // we need to hear users
       selfMute: false,
     });
@@ -102,6 +122,20 @@ export class VoiceSession {
     this.attachReceiver();
   }
 
+  /** The shared session for single-account Go-Live, or null if session_id isn't
+   *  captured yet / the client is unavailable. */
+  getSharedSession(): {
+    client: unknown;
+    guildId: string;
+    channelId: string;
+    sessionId: string;
+    botId: string;
+  } | null {
+    const botId = this.client?.user?.id;
+    if (!this.sessionId || !this.client || !botId) return null;
+    return { client: this.client, guildId: this.guildId, channelId: this.channelId, sessionId: this.sessionId, botId };
+  }
+
   async ready(): Promise<void> {
     await entersState(this.connection, VoiceConnectionStatus.Ready, 20_000);
   }