telegram: exit when Claude Code closes the connection

When the MCP stdio transport closes, the bot kept polling Telegram as
a zombie process — holding the token and causing 409 Conflict for the
next session.

- Listen for stdin end/close and SIGTERM/SIGINT -> bot.stop() + exit
- Force-exit after 2s if bot.stop() stalls on the long-poll timeout
- unref the approval-check interval so it doesn't keep us alive

Fixes #793, partial #788 (issue 3)

external_plugins/telegram/server.ts

@@ -51,15 +51,6 @@ 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(`telegram channel: unhandled rejection: ${err}\n`)
-})
-process.on('uncaughtException', err => {
-  process.stderr.write(`telegram channel: uncaught exception: ${err}\n`)
-})
-
 const bot = new Bot(TOKEN)
 let botUsername = ''
 
@@ -313,7 +304,7 @@ function checkApprovals(): void {
   }
 }
 
-if (!STATIC) setInterval(checkApprovals, 5000)
+if (!STATIC) setInterval(checkApprovals, 5000).unref()
 
 // Telegram caps messages at 4096 chars. Split long replies, preferring
 // paragraph boundaries when chunkMode is 'newline'.
@@ -516,6 +507,24 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
 
 await mcp.connect(new StdioServerTransport())
 
+// When Claude Code closes the MCP connection, stdin gets EOF. Without this
+// the bot keeps polling forever as a zombie, holding the token and blocking
+// the next session with 409 Conflict.
+let shuttingDown = false
+function shutdown(): void {
+  if (shuttingDown) return
+  shuttingDown = true
+  process.stderr.write('telegram channel: shutting down\n')
+  // bot.stop() signals the poll loop to end; the current getUpdates request
+  // may take up to its long-poll timeout to return. Force-exit after 2s.
+  setTimeout(() => process.exit(0), 2000)
+  void Promise.resolve(bot.stop()).finally(() => process.exit(0))
+}
+process.stdin.on('end', shutdown)
+process.stdin.on('close', shutdown)
+process.on('SIGTERM', shutdown)
+process.on('SIGINT', shutdown)
+
 bot.on('message:text', async ctx => {
   await handleInbound(ctx, ctx.message.text, undefined)
 })
@@ -586,7 +595,7 @@ async function handleInbound(
 
   // image_path goes in meta only — an in-content "[image attached — read: PATH]"
   // annotation is forgeable by any allowlisted sender typing that string.
-  mcp.notification({
+  void mcp.notification({
     method: 'notifications/claude/channel',
     params: {
       content: text,
@@ -599,25 +608,12 @@ async function handleInbound(
         ...(imagePath ? { image_path: imagePath } : {}),
       },
     },
-  }).catch(err => {
-    process.stderr.write(`telegram channel: failed to deliver inbound to Claude: ${err}\n`)
   })
 }
 
-// Without this, any throw in a message handler stops polling permanently
-// (grammy's default error handler calls bot.stop() and rethrows).
-bot.catch(err => {
-  process.stderr.write(`telegram channel: handler error (polling continues): ${err.error}\n`)
-})
-
-bot.start({
+void bot.start({
   onStart: info => {
     botUsername = info.username
     process.stderr.write(`telegram channel: polling as @${info.username}\n`)
   },
-}).catch(err => {
-  // bot.start() only rejects if polling can't begin or dies unrecoverably —
-  // bad token, 409 conflict, network gone. Log it so the user isn't left
-  // wondering why messages stopped arriving.
-  process.stderr.write(`telegram channel: polling stopped: ${err}\n`)
 })