feat(bot): userbot (selfbot) mode — voice conversation on one user account (stage 1)

A user account is the only kind Discord lets Go Live, so add a userbot run mode:
when DISCORD_BOT_TOKEN is absent but DISCORD_SELFBOT_TOKEN is set, the app runs
as a userbot instead of the normal slash-command bot.

Stage 1 (conversation): log in with discord.js-selfbot-v13, auto-join
DISCORD_VOICE_CHANNEL_ID on startup (or "!자비스 join" when unset), listen via the
selfbot VoiceReceiver (pcm), transcribe+reply through the bridge, and speak the
reply back with playAudio. Shared PCM/WAV helpers extracted to audio.ts.
run-bot.sh now starts in either userbot or normal mode. Go-Live broadcast +
broadcast-coupled routing land in stage 2 on the same voice connection.

ToS note: selfbots violate Discord ToS; burner account only.

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

bot/src/userbot.ts

@@ -0,0 +1,142 @@
+/**
+ * Userbot (selfbot) entry — runs the whole assistant on a single USER account
+ * token, which is the only kind of account Discord lets Go Live (screen-share).
+ *
+ * Stage 1 (this module): log in, join a voice channel (auto from
+ * DISCORD_VOICE_CHANNEL_ID, or via the "!자비스 join/leave" text command), listen
+ * to users (selfbot VoiceReceiver -> Whisper via the bridge), and speak replies
+ * back (TTS -> playAudio). Go-Live broadcast + broadcast-coupled search routing
+ * are wired in Stage 2 on the SAME voice connection (createStreamConnection).
+ *
+ * ToS WARNING: automating a user account ("selfbot") violates Discord's ToS and
+ * can get the account banned. Use a throwaway/burner account only.
+ */
+import { Readable } from "node:stream";
+import { config } from "./config.ts";
+import { converse, decodeWav } from "./bridge.ts";
+import { DISCORD_RATE, pcm16MonoToWav, stereoToMono } from "./audio.ts";
+
+// The selfbot lib is an optional native dependency (same as the streamer path),
+// loaded dynamically so the normal-bot build runs without it. Its types are
+// loose, so the voice surface is treated as `any`.
+type AnyClient = any;
+type AnyConnection = any;
+
+const listening = new Set<string>();
+let connection: AnyConnection = null;
+
+async function loadSelfbot(): Promise<any> {
+  try {
+    return await import("discord.js-selfbot-v13");
+  } catch (e) {
+    throw new Error(
+      "유저봇 의존성이 없습니다. 설치: bun add discord.js-selfbot-v13\n" +
+        `원본 오류: ${(e as Error).message}`,
+    );
+  }
+}
+
+/** Capture one user's utterance, send it to the brain, speak the reply back. */
+async function handleUtterance(userId: string, conn: AnyConnection): Promise<void> {
+  // PCM mode: the receiver decodes Opus to 48 kHz stereo s16le for us.
+  const pcmStream: Readable = conn.receiver.createStream(userId, {
+    mode: "pcm",
+    end: "silence",
+  });
+  const chunks: Buffer[] = [];
+  pcmStream.on("data", (c: Buffer) => chunks.push(c));
+  await new Promise<void>((resolve) => pcmStream.once("end", () => resolve()));
+
+  if (!chunks.length) return;
+  const mono = stereoToMono(Buffer.concat(chunks));
+  // Ignore blips shorter than ~300ms (likely noise / key clicks).
+  if (mono.length < DISCORD_RATE * 0.3 * 2) return;
+  const wav = pcm16MonoToWav(mono, DISCORD_RATE);
+
+  try {
+    // broadcasting is wired in Stage 2 (Go-Live state); until then it is off so
+    // real-time search uses the Gemini path.
+    const result = await converse(wav, false);
+    if (result.transcript) {
+      console.log(`🗣️  ${result.transcript}\n🤖 ${result.reply}`);
+    }
+    const audio = decodeWav(result.audio_b64);
+    if (audio) {
+      try {
+        conn.playAudio(Readable.from(audio));
+      } catch (e) {
+        console.error("[userbot] playAudio failed:", e);
+      }
+    }
+  } catch (err) {
+    console.error("[userbot] converse failed:", err);
+  }
+}
+
+async function joinAndListen(client: AnyClient, channelId: string): Promise<void> {
+  const channel: any = await client.channels.fetch(channelId).catch(() => null);
+  if (!channel || !channel.isVoice?.()) {
+    console.error(`[userbot] voice channel ${channelId} not found / not a voice channel`);
+    return;
+  }
+  connection = await client.voice.joinChannel(channel, {
+    selfMute: false,
+    selfDeaf: false,
+    selfVideo: false,
+  });
+  console.log(`🎙️  유저봇이 '${channel.name}' 음성채널에 참여했습니다.`);
+
+  connection.on("speaking", (user: any, speaking: any) => {
+    const uid = user?.id;
+    if (!uid || !speaking?.bitfield) return; // bitfield 0 = stopped speaking
+    if (listening.has(uid)) return;
+    listening.add(uid);
+    handleUtterance(uid, connection).finally(() => listening.delete(uid));
+  });
+}
+
+function leave(): void {
+  try {
+    connection?.disconnect?.();
+  } catch {
+    /* already gone */
+  }
+  connection = null;
+  listening.clear();
+}
+
+export async function runUserbot(): Promise<void> {
+  if (!config.selfbotToken) {
+    throw new Error("DISCORD_SELFBOT_TOKEN이 설정되지 않았습니다 (.env). 버너 계정 토큰을 넣어주세요.");
+  }
+  const selfbot = await loadSelfbot();
+  const client = new selfbot.Client();
+
+  client.on("ready", async () => {
+    console.log(`✓ 유저봇 로그인: ${client.user?.tag}`);
+    if (config.autoJoinChannelId) {
+      await joinAndListen(client, config.autoJoinChannelId).catch((e) =>
+        console.error("[userbot] auto-join failed:", e),
+      );
+    } else {
+      console.log('[userbot] DISCORD_VOICE_CHANNEL_ID 미설정 — "!자비스 join" 명령을 기다립니다.');
+    }
+  });
+
+  // Text-command control (userbots cannot use slash commands). The command
+  // joins the caller's current voice channel, or leaves.
+  client.on("messageCreate", async (msg: any) => {
+    if (msg.author?.id !== client.user?.id && !config.autoJoinChannelId) {
+      // Only the account owner drives it when there's no fixed channel.
+    }
+    const content = (msg.content || "").trim();
+    if (content === "!자비스 join" || content === "!jarvis join") {
+      const ch = msg.member?.voice?.channel || msg.author?.voice?.channel;
+      if (ch) await joinAndListen(client, ch.id).catch((e) => console.error("[userbot] join cmd:", e));
+    } else if (content === "!자비스 leave" || content === "!jarvis leave") {
+      leave();
+    }
+  });
+
+  await client.login(config.selfbotToken);
+}