Add Bun prerequisite to discord and telegram plugin READMEs

Both MCP servers run on Bun, but this wasn't documented. Add a
Prerequisites section with the install command so users don't hit
a missing-runtime error on first setup.

external_plugins/discord/README.md

@@ -4,6 +4,9 @@ Connect a Discord bot to your Claude Code with an MCP server.
 
 When the bot receives a message, the MCP server forwards it to Claude and provides tools to reply, react, and edit messages.
 
+## Prerequisites
+
+- [Bun](https://bun.sh) — the MCP server runs on Bun. Install with `curl -fsSL https://bun.sh/install | bash`.
 
 ## Quick Setup
 > Default pairing flow for a single-user DM bot. See [ACCESS.md](./ACCESS.md) for groups and multi-user setups.

external_plugins/telegram/README.md

@@ -4,6 +4,10 @@ Connect a Telegram bot to your Claude Code with an MCP server.
 
 The MCP server logs into Telegram as a bot and provides tools to Claude to reply, react, or edit messages. When you message the bot, the server forwards the message to your Claude Code session.
 
+## Prerequisites
+
+- [Bun](https://bun.sh) — the MCP server runs on Bun. Install with `curl -fsSL https://bun.sh/install | bash`.
+
 ## Quick Setup
 > Default pairing flow for a single-user DM bot. See [ACCESS.md](./ACCESS.md) for groups and multi-user setups.