[FEATURE] Discord plugin: support multiple bot tokens per machine for multi-session setups

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Problem
The Discord plugin (discord@claude-plugins-official) stores a single bot token in ~/.claude/channels/discord/.env. This means only one Claude Code CLI session per machine can connect to Discord at a time.

When running multiple claude --channels plugin:discord@claude-plugins-official sessions on the same machine (e.g., one session per project, each paired to a different Discord channel), only the first session successfully connects to the Discord gateway. Subsequent sessions silently fail to receive messages.

Current workaround
Only one session per machine gets Discord access
Cross-machine: create a separate bot per machine, each with its own token

Proposed Solution

Suggested fix
Support per-session or per-project bot token configuration. Possible approaches:
Allow DISCORD_BOT_TOKEN in a project-level config (e.g., .mcp.json or project .env)
Add a --discord-token CLI flag
Support a ~/.claude/channels/discord/tokens/<session-id>.env pattern
Allow the --channels flag to accept a config argument (e.g., --channels plugin:discord@claude-plugins-official:token=<token>)

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

MCP server integration

Use Case Example

I run separate Claude Code sessions for different projects (e.g., Obsidian vault management, research paper, app development). I set up a Discord server with one channel per project so I can interact with each session from my phone. This works across machines (each machine has its own .env with a different bot token), but not for multiple sessions on the same machine.

Additional Context

_No response_