fix(telegram): separate thread params for typing vs messages

Telegram General topic (id=1) has inconsistent API behavior:
- sendMessage: rejects explicit message_thread_id=1
- sendChatAction: requires message_thread_id=1 for typing to show

Split into two helper functions:
- buildTelegramThreadParams: excludes General topic for messages
- buildTypingThreadParams: includes General topic for typing

src/telegram/bot-message-context.ts

@@ -18,6 +18,7 @@ import {
   buildTelegramGroupFrom,
   buildTelegramGroupPeerId,
   buildTelegramThreadParams,
+  buildTypingThreadParams,
   describeReplyTarget,
   extractTelegramLocation,
   hasBotMention,
@@ -92,7 +93,7 @@ export const buildTelegramMessageContext = async ({
 
   const sendTyping = async () => {
     try {
-      await bot.api.sendChatAction(chatId, "typing", buildTelegramThreadParams(resolvedThreadId));
+      await bot.api.sendChatAction(chatId, "typing", buildTypingThreadParams(resolvedThreadId));
     } catch (err) {
       logVerbose(`telegram typing cue failed for chat ${chatId}: ${String(err)}`);
     }

src/telegram/bot/helpers.ts

@@ -19,8 +19,27 @@ export function resolveTelegramForumThreadId(params: {
   return params.messageThreadId ?? undefined;
 }
 
+/**
+ * Build thread params for Telegram API calls (messages, media).
+ * Excludes General topic (id=1) as Telegram rejects explicit message_thread_id=1
+ * for sendMessage calls in forum supergroups ("message thread not found" error).
+ */
 export function buildTelegramThreadParams(messageThreadId?: number) {
-  return messageThreadId != null ? { message_thread_id: messageThreadId } : undefined;
+  if (messageThreadId == null || messageThreadId === TELEGRAM_GENERAL_TOPIC_ID) {
+    return undefined;
+  }
+  return { message_thread_id: messageThreadId };
+}
+
+/**
+ * Build thread params for typing indicators (sendChatAction).
+ * Unlike sendMessage, sendChatAction accepts message_thread_id=1 for General topic.
+ */
+export function buildTypingThreadParams(messageThreadId?: number) {
+  if (messageThreadId == null) {
+    return undefined;
+  }
+  return { message_thread_id: messageThreadId };
 }
 
 export function resolveTelegramStreamMode(

src/telegram/send.ts

@@ -20,6 +20,7 @@ import { markdownToTelegramHtml } from "./format.js";
 import { recordSentMessage } from "./sent-message-cache.js";
 import { parseTelegramTarget, stripTelegramInternalPrefixes } from "./targets.js";
 import { resolveTelegramVoiceSend } from "./voice.js";
+import { buildTelegramThreadParams } from "./bot/helpers.js";
 
 type TelegramSendOpts = {
   token?: string;
@@ -166,12 +167,10 @@ export async function sendMessageTelegram(
 
   // Build optional params for forum topics and reply threading.
   // Only include these if actually provided to keep API calls clean.
-  const threadParams: Record<string, number> = {};
   const messageThreadId =
     opts.messageThreadId != null ? opts.messageThreadId : target.messageThreadId;
-  if (messageThreadId != null) {
-    threadParams.message_thread_id = Math.trunc(messageThreadId);
-  }
+  const threadIdParams = buildTelegramThreadParams(messageThreadId);
+  const threadParams: Record<string, number> = threadIdParams ? { ...threadIdParams } : {};
   if (opts.replyToMessageId != null) {
     threadParams.reply_to_message_id = Math.trunc(opts.replyToMessageId);
   }