feat(setup): clarify @BotFather is Telegram's official bot

Step 1 of the Telegram channel's BotFather instructions used to read:

  1. Open Telegram and message @BotFather

Two small UX issues with that:
  - "BotFather" reads slightly sketchy without context — a first-time
    user has no way to know it's the official, sanctioned account
    rather than an impersonator.
  - Typing the username from memory leaves room for picking a typo'd
    impostor account (Telegram has many @BotF4ther / @BotFAther / etc.
    look-alikes).

Update the line so the official-bot framing is part of the instruction
itself:

  1. Open Telegram and message @BotFather — Telegram's official bot
     for creating and managing bots

One-line change in the existing note() body. No new dependencies, no
asset churn, no other behavior change.

setup/channels/telegram.ts

@@ -149,7 +149,7 @@ async function collectTelegramToken(): Promise<string> {
       "Your assistant talks to you through a Telegram bot you create.",
       "Here's how:",
       '',
-      '  1. Open Telegram and message @BotFather',
+      "  1. Open Telegram and message @BotFather — Telegram's official bot for creating and managing bots",
       '  2. Send /newbot and follow the prompts',
       '  3. Copy the token it gives you (it looks like <digits>:<chars>)',
       '',