Feature Request: Per-project Telegram bot token support

Problem

The Telegram plugin currently stores the bot token in a single global config file (~/.claude/channels/telegram/.env). This means all Claude Code sessions across different projects must share the same Telegram bot.

Use Case

When running multiple Claude Code sessions for different projects simultaneously (e.g., one session for Project A, another for Project B), there is no way to connect each session to its own dedicated Telegram bot. Switching projects requires manually replacing the token and restarting the session.

Proposed Solution

Support a project-level Telegram config that takes precedence over the global config:

• Project-level: .claude/channels/telegram/.env (in the project root)
• Global fallback: ~/.claude/channels/telegram/.env (current behavior)

This would allow each project to have its own dedicated bot, enabling multiple Claude Code sessions to run simultaneously with independent Telegram channels.

Expected Behavior

• Each Claude Code session reads its project-level .env first, falling back to the global one
• Multiple sessions can poll different bots simultaneously without conflict
• /telegram:configure sets the project-level token when run inside a project

Current Behavior

All sessions share a single global bot token. Switching projects requires manually editing ~/.claude/channels/telegram/.env and restarting the session.