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

@@ -304,7 +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'.
@@ -372,11 +372,6 @@ mcp.setRequestHandler(ListToolsRequestSchema, async () => ({
             items: { type: 'string' },
             description: 'Absolute file paths to attach. Images send as photos (inline preview); other types as documents. Max 50MB each.',
           },
-          format: {
-            type: 'string',
-            enum: ['text', 'markdownv2'],
-            description: "Rendering mode. 'markdownv2' enables Telegram formatting (bold, italic, code, links). Caller must escape special chars per MarkdownV2 rules. Default: 'text' (plain, no escaping needed).",
-          },
         },
         required: ['chat_id', 'text'],
       },
@@ -403,11 +398,6 @@ mcp.setRequestHandler(ListToolsRequestSchema, async () => ({
           chat_id: { type: 'string' },
           message_id: { type: 'string' },
           text: { type: 'string' },
-          format: {
-            type: 'string',
-            enum: ['text', 'markdownv2'],
-            description: "Rendering mode. 'markdownv2' enables Telegram formatting (bold, italic, code, links). Caller must escape special chars per MarkdownV2 rules. Default: 'text' (plain, no escaping needed).",
-          },
         },
         required: ['chat_id', 'message_id', 'text'],
       },
@@ -424,8 +414,6 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
         const text = args.text as string
         const reply_to = args.reply_to != null ? Number(args.reply_to) : undefined
         const files = (args.files as string[] | undefined) ?? []
-        const format = (args.format as string | undefined) ?? 'text'
-        const parseMode = format === 'markdownv2' ? 'MarkdownV2' as const : undefined
 
         assertAllowedChat(chat_id)
 
@@ -452,7 +440,6 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
               (replyMode === 'all' || i === 0)
             const sent = await bot.api.sendMessage(chat_id, chunks[i], {
               ...(shouldReplyTo ? { reply_parameters: { message_id: reply_to } } : {}),
-              ...(parseMode ? { parse_mode: parseMode } : {}),
             })
             sentIds.push(sent.message_id)
           }
@@ -495,13 +482,10 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
       }
       case 'edit_message': {
         assertAllowedChat(args.chat_id as string)
-        const editFormat = (args.format as string | undefined) ?? 'text'
-        const editParseMode = editFormat === 'markdownv2' ? 'MarkdownV2' as const : undefined
         const edited = await bot.api.editMessageText(
           args.chat_id as string,
           Number(args.message_id),
           args.text as string,
-          ...(editParseMode ? [{ parse_mode: editParseMode }] : []),
         )
         const id = typeof edited === 'object' ? edited.message_id : args.message_id
         return { content: [{ type: 'text', text: `edited (id: ${id})` }] }
@@ -523,6 +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)
 })