fix(redstone): use plain reply in non-private chats (TEXTDRAFT_PEER_INVALID)

sendMessageDraft (Bot API 9.5) only works in private chats. Group,
supergroup and channel peers reject it with TEXTDRAFT_PEER_INVALID,
so Redstone was silently failing the entire reply path in groups
after the streaming feature landed in cab5337.

Keep replyWithStream for private chats (the typing animation is
the whole point); fall back to plain ctx.reply() everywhere else.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

bot/bot.ts

@@ -1460,10 +1460,19 @@ bot.on("message:text", async (ctx) => {
   // Stream the reply word-by-word so the message animates into the chat like
   // an LLM typing. @grammyjs/stream uses sendMessageDraft (Bot API 9.5) to push
   // each delta as a native, animated draft and finalizes with sendMessage.
+  // sendMessageDraft is only supported in private chats — group / supergroup
+  // / channel peers return TEXTDRAFT_PEER_INVALID. Use plain reply there.
+  let finalMessage: { message_id: number } | undefined;
+  if (chatType === "private") {
     const messages = await ctx.replyWithStream(streamWords(out), {}, {
       reply_parameters: { message_id: ctx.message.message_id },
     });
-  const finalMessage = messages[messages.length - 1];
+    finalMessage = messages[messages.length - 1];
+  } else {
+    finalMessage = await ctx.reply(out, {
+      reply_parameters: { message_id: ctx.message.message_id },
+    });
+  }
   if (finalMessage) {
     Q.insMsg.run(chatId, finalMessage.message_id, null, "out", "text", out, ctx.message.message_id);
   }