Add Telegram Bot API channel as WASM module

Implements a loadable WASM channel for Telegram following the existing
Slack channel pattern:

- Webhook-based message receiving at /webhook/telegram
- Private chat and group chat support (with @mention filtering)
- Reply threading via reply_to_message_id
- User name extraction from Telegram user objects
- Bot token injection by host (never exposed to WASM)

Files:
- channels-src/telegram/src/lib.rs - Main implementation
- channels-src/telegram/Cargo.toml - Dependencies
- channels-src/telegram/telegram.capabilities.json - Permissions
- channels-src/telegram/build.sh - Build script

To use: copy telegram.wasm and telegram.capabilities.json to
~/.near-agent/channels/ and configure telegram_bot_token secret.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

CLAUDE.md

@@ -351,7 +351,7 @@ Inspired by [OpenClaw](https://github.com/openclaw/openclaw), the workspace prov
 
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