discord: port resilience fixes from telegram

Same patterns as #812/#813 for the discord channel:
- process-level unhandledRejection/uncaughtException handlers
- client.on('error') to log discord.js errors
- mcp.notification().catch() so inbound delivery failures surface
- stdin close / SIGTERM -> client.destroy() + exit (zombie fix)
- .unref() the approval-check interval
- client.login().catch() to log+exit on bad token instead of crashing

Discord is inherently more resilient than telegram (discord.js
auto-reconnects, no 409 equivalent), but these gaps were still there.

external_plugins/discord/server.ts

@@ -58,6 +58,15 @@ if (!TOKEN) {
 }
 const INBOX_DIR = join(STATE_DIR, 'inbox')
 
+// Last-resort safety net — without these the process dies silently on any
+// unhandled promise rejection. With them it logs and keeps serving tools.
+process.on('unhandledRejection', err => {
+  process.stderr.write(`discord channel: unhandled rejection: ${err}\n`)
+})
+process.on('uncaughtException', err => {
+  process.stderr.write(`discord channel: uncaught exception: ${err}\n`)
+})
+
 const client = new Client({
   intents: [
     GatewayIntentBits.DirectMessages,
@@ -342,7 +351,7 @@ function checkApprovals(): void {
   }
 }
 
-if (!STATIC) setInterval(checkApprovals, 5000)
+if (!STATIC) setInterval(checkApprovals, 5000).unref()
 
 // Discord caps messages at 2000 chars (hard limit — larger sends reject).
 // Split long replies, preferring paragraph boundaries when chunkMode is
@@ -637,6 +646,25 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
 
 await mcp.connect(new StdioServerTransport())
 
+// When Claude Code closes the MCP connection, stdin gets EOF. Without this
+// the gateway stays connected as a zombie holding resources.
+let shuttingDown = false
+function shutdown(): void {
+  if (shuttingDown) return
+  shuttingDown = true
+  process.stderr.write('discord channel: shutting down\n')
+  setTimeout(() => process.exit(0), 2000)
+  void Promise.resolve(client.destroy()).finally(() => process.exit(0))
+}
+process.stdin.on('end', shutdown)
+process.stdin.on('close', shutdown)
+process.on('SIGTERM', shutdown)
+process.on('SIGINT', shutdown)
+
+client.on('error', err => {
+  process.stderr.write(`discord channel: client error: ${err}\n`)
+})
+
 client.on('messageCreate', msg => {
   if (msg.author.bot) return
   handleInbound(msg).catch(e => process.stderr.write(`discord: handleInbound failed: ${e}\n`))
@@ -685,7 +713,7 @@ async function handleInbound(msg: Message): Promise<void> {
   // forgeable by any allowlisted sender typing that string.
   const content = msg.content || (atts.length > 0 ? '(attachment)' : '')
 
-  void mcp.notification({
+  mcp.notification({
     method: 'notifications/claude/channel',
     params: {
       content,
@@ -698,6 +726,8 @@ async function handleInbound(msg: Message): Promise<void> {
         ...(atts.length > 0 ? { attachment_count: String(atts.length), attachments: atts.join('; ') } : {}),
       },
     },
+  }).catch(err => {
+    process.stderr.write(`discord channel: failed to deliver inbound to Claude: ${err}\n`)
   })
 }
 
@@ -705,4 +735,7 @@ client.once('ready', c => {
   process.stderr.write(`discord channel: gateway connected as ${c.user.tag}\n`)
 })
 
-await client.login(TOKEN)
+client.login(TOKEN).catch(err => {
+  process.stderr.write(`discord channel: login failed: ${err}\n`)
+  process.exit(1)
+})

external_plugins/telegram/server.ts

@@ -507,62 +507,6 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
 
 await mcp.connect(new StdioServerTransport())
 
-// Commands are DM-only. Responding in groups would: (1) leak pairing codes via
-// /status to other group members, (2) confirm bot presence in non-allowlisted
-// groups, (3) spam channels the operator never approved. Silent drop matches
-// the gate's behavior for unrecognized groups.
-
-bot.command('start', async ctx => {
-  if (ctx.chat?.type !== 'private') return
-  const access = loadAccess()
-  if (access.dmPolicy === 'disabled') {
-    await ctx.reply(`This bot isn't accepting new connections.`)
-    return
-  }
-  await ctx.reply(
-    `This bot bridges Telegram to a Claude Code session.\n\n` +
-    `To pair:\n` +
-    `1. DM me anything — you'll get a 6-char code\n` +
-    `2. In Claude Code: /telegram:access pair <code>\n\n` +
-    `After that, DMs here reach that session.`
-  )
-})
-
-bot.command('help', async ctx => {
-  if (ctx.chat?.type !== 'private') return
-  await ctx.reply(
-    `Messages you send here route to a paired Claude Code session. ` +
-    `Text and photos are forwarded; replies and reactions come back.\n\n` +
-    `/start — pairing instructions\n` +
-    `/status — check your pairing state`
-  )
-})
-
-bot.command('status', async ctx => {
-  if (ctx.chat?.type !== 'private') return
-  const from = ctx.from
-  if (!from) return
-  const senderId = String(from.id)
-  const access = loadAccess()
-
-  if (access.allowFrom.includes(senderId)) {
-    const name = from.username ? `@${from.username}` : senderId
-    await ctx.reply(`Paired as ${name}.`)
-    return
-  }
-
-  for (const [code, p] of Object.entries(access.pending)) {
-    if (p.senderId === senderId) {
-      await ctx.reply(
-        `Pending pairing — run in Claude Code:\n\n/telegram:access pair ${code}`
-      )
-      return
-    }
-  }
-
-  await ctx.reply(`Not paired. Send me a message to get a pairing code.`)
-})
-
 bot.on('message:text', async ctx => {
   await handleInbound(ctx, ctx.message.text, undefined)
 })
@@ -653,13 +597,5 @@ void bot.start({
   onStart: info => {
     botUsername = info.username
     process.stderr.write(`telegram channel: polling as @${info.username}\n`)
-    void bot.api.setMyCommands(
-      [
-        { command: 'start', description: 'Welcome and setup guide' },
-        { command: 'help', description: 'What this bot can do' },
-        { command: 'status', description: 'Check your pairing status' },
-      ],
-      { scope: { type: 'all_private_chats' } },
-    ).catch(() => {})
   },
 })