Add Discord-native hybrid front-end for Jarvis (bot + bridge)

Transform isair/jarvis into a Discord-controlled voice assistant running on
the Ubuntu VNC desktop, keeping the mature ~39k-line Python brain intact.

- bot/ (Node + bun, discord.js): /자비스 slash commands (ephemeral),
  voice channel join + voice receive/playback, pluggable VNC screen broadcast
  (selfbot live / noVNC / screenshot)
- bridge/ (Python, Flask): wraps jarvis STT + run_reply_engine + Piper TTS
  behind a thin localhost HTTP API
- .env.example, scripts/ (start_bridge/start_bot/dev), README rewrite,
  docs/language-comparison.md and docs/vnc-xfce-setup.md

Language decision: hybrid (Python brain + Node/bun Discord layer) because
Discord blocks bot video; native screen broadcast only works via a Node
selfbot library.

bot/src/index.ts

@@ -0,0 +1,148 @@
+/**
+ * Javis bot entry point.
+ *
+ * A normal Discord bot that:
+ *  - exposes /자비스 (join / leave / ask / stream / stop / status)
+ *  - replies to every slash command EPHEMERALLY (only the invoker sees it)
+ *  - joins the caller's voice channel for live voice conversation (brain in bridge/)
+ *  - broadcasts the VNC screen via a pluggable backend (selfbot / novnc / screenshot)
+ */
+import {
+  Client,
+  GatewayIntentBits,
+  MessageFlags,
+  type ChatInputCommandInteraction,
+  type GuildMember,
+  type TextBasedChannel,
+} from "discord.js";
+import { AttachmentBuilder } from "discord.js";
+import { config } from "./config.ts";
+import { ask, health } from "./bridge.ts";
+import { joinChannel, leaveGuild, getSession } from "./voice.ts";
+import { createStreamer, type ScreenStreamer, type StreamContext } from "./stream/index.ts";
+
+const client = new Client({
+  intents: [GatewayIntentBits.Guilds, GatewayIntentBits.GuildVoiceStates],
+});
+
+const streamers = new Map<string, ScreenStreamer>();
+
+async function getStreamer(guildId: string): Promise<ScreenStreamer> {
+  let s = streamers.get(guildId);
+  if (!s) {
+    s = await createStreamer(config);
+    streamers.set(guildId, s);
+  }
+  return s;
+}
+
+const eph = { flags: MessageFlags.Ephemeral } as const;
+
+client.once("clientReady", () => {
+  console.log(`✓ 로그인: ${client.user?.tag} | stream backend: ${config.streamBackend}`);
+});
+
+client.on("interactionCreate", async (interaction) => {
+  if (!interaction.isChatInputCommand()) return;
+  if (interaction.commandName !== "자비스") return;
+  const i = interaction as ChatInputCommandInteraction;
+  const sub = i.options.getSubcommand();
+
+  try {
+    switch (sub) {
+      case "join":
+        return void (await handleJoin(i));
+      case "leave":
+        return void (await handleLeave(i));
+      case "ask":
+        return void (await handleAsk(i));
+      case "stream":
+        return void (await handleStream(i));
+      case "stop":
+        return void (await handleStop(i));
+      case "status":
+        return void (await handleStatus(i));
+    }
+  } catch (err) {
+    console.error(`[/자비스 ${sub}]`, err);
+    const msg = `오류: ${(err as Error).message}`;
+    if (i.deferred || i.replied) await i.editReply(msg);
+    else await i.reply({ content: msg, ...eph });
+  }
+});
+
+async function handleJoin(i: ChatInputCommandInteraction) {
+  const member = i.member as GuildMember;
+  const channel = member?.voice?.channel;
+  if (!channel) {
+    return i.reply({ content: "먼저 음성 채널에 들어간 뒤 다시 호출해주세요.", ...eph });
+  }
+  await i.deferReply(eph);
+  const session = await joinChannel(channel);
+  session.onTurn = ({ transcript, reply }) =>
+    console.log(`🗣️  ${transcript}\n🤖 ${reply}`);
+  await i.editReply(`🎙️ '${channel.name}' 채널에 접속했습니다. 말씀하세요.`);
+}
+
+async function handleLeave(i: ChatInputCommandInteraction) {
+  const left = leaveGuild(i.guildId!);
+  await i.reply({ content: left ? "음성 채널에서 나갔습니다." : "접속 중인 세션이 없습니다.", ...eph });
+}
+
+async function handleAsk(i: ChatInputCommandInteraction) {
+  const q = i.options.getString("질문", true);
+  await i.deferReply(eph);
+  const res = await ask(q);
+  const reply = res.reply || res.error || "(응답 없음)";
+  await i.editReply(reply.slice(0, 1900));
+}
+
+async function handleStream(i: ChatInputCommandInteraction) {
+  const member = i.member as GuildMember;
+  await i.deferReply(eph);
+  const streamer = await getStreamer(i.guildId!);
+  const ctx: StreamContext = {
+    guildId: i.guildId!,
+    voiceChannelId: member?.voice?.channelId ?? "",
+    postImage: async (png, name) => {
+      const ch = i.channel as TextBasedChannel | null;
+      if (ch && "send" in ch) {
+        await (ch as any).send({ files: [new AttachmentBuilder(png, { name })] });
+      }
+    },
+  };
+  if (config.streamBackend === "selfbot" && !ctx.voiceChannelId) {
+    return i.editReply("셀프봇 송출은 음성 채널 안에서 호출해야 합니다. 음성 채널에 들어간 뒤 다시 시도하세요.");
+  }
+  const msg = await streamer.start(ctx);
+  await i.editReply(msg);
+}
+
+async function handleStop(i: ChatInputCommandInteraction) {
+  const streamer = streamers.get(i.guildId!);
+  if (!streamer) return i.reply({ content: "송출 중이 아닙니다.", ...eph });
+  await streamer.stop();
+  await i.reply({ content: "송출을 중단했습니다.", ...eph });
+}
+
+async function handleStatus(i: ChatInputCommandInteraction) {
+  await i.deferReply(eph);
+  let brain = "unreachable";
+  try {
+    const h = await health();
+    brain = h.brain_ready ? "ready" : `not-ready${h.brain_error ? " (" + h.brain_error + ")" : ""}`;
+  } catch {
+    /* keep unreachable */
+  }
+  const session = getSession(i.guildId!);
+  const streamer = streamers.get(i.guildId!);
+  await i.editReply(
+    [
+      `브릿지 두뇌: ${brain}`,
+      `음성 세션: ${session ? "접속 중" : "없음"}`,
+      `송출 백엔드: ${config.streamBackend} (${streamer?.isActive() ? "활성" : "대기"})`,
+    ].join("\n"),
+  );
+}
+
+client.login(config.botToken);