[Bug] Discord channel plugin process not terminated on session end — orphan processes accumulate

Bug Description

When a Claude Code session ends (/exit or Ctrl+C), the Discord channel plugin server process (bun run --cwd .../discord/0.0.1 --shell=bun --silent start) is not terminated and remains as an orphan process.

Starting a new session with --channels plugin:discord@claude-plugins-official spawns a new process without killing the previous one, causing duplicate processes to compete for the same Discord bot token.

Steps to Reproduce

1. Start Claude Code with Discord channel: claude --channels plugin:discord@claude-plugins-official
2. Verify Discord plugin process is running: ps aux | grep "discord.*start"
3. Exit Claude Code session (/exit or Ctrl+C)
4. Start a new session with the same command
5. Check processes again: ps aux | grep "discord.*start"

Result: Two Discord plugin processes are running simultaneously.

Expected Behavior

The previous session's Discord channel server process should be terminated when the session ends, before spawning a new one.

Impact

• Duplicate processes cause state contention on the Discord bot token
• reply calls intermittently fail with "channel is not allowlisted" even though access.json correctly has the channel allowlisted
• Users need to manually pkill -f "discord.*start" to resolve

Environment

• Claude Code version: 2.1.81
• OS: macOS (Darwin 25.3.0)
• Discord plugin: claude-plugins-official/discord/0.0.1
• Runtime: Bun

Workaround

Manually kill orphan processes before starting a new session:

pkill -f "discord.*start"