feat(plugins): add notifier plugin for cross-platform notifications

[js-koo]

Summary

• Add a notification plugin that alerts users when Claude Code completes tasks, requests permissions, or waits for input
• Cross-platform support: macOS, Linux, Windows (Native/WSL2)
• Smart notifications: only notifies for tasks taking 20+ seconds (configurable)
• Session-aware: multiple Claude Code sessions work independently

Features

Feature	Description
Cross-platform	macOS (osascript), Linux (notify-send), Windows (PowerShell toast)
Smart timing	Configurable minimum duration threshold (default: 20 seconds)
Prompt preview	Shows first N characters of original prompt in notification
Bilingual	English and Korean language support
Slash command	/notifier for easy configuration

Hooks Used

• UserPromptSubmit: Saves prompt text and start timestamp
• Stop: Shows completion notification (if duration > threshold)
• Notification: Alerts for permission_prompt and idle_prompt
• SessionEnd: Cleans up temporary session files

Configuration

/notifier status       # Show current settings
/notifier lang ko      # Set language (en/ko)
/notifier duration 30  # Set minimum duration (seconds)
/notifier preview 60   # Set prompt preview length
/notifier test         # Send test notification

Tested Environments

Platform	Status
macOS	✅ Tested
Linux	✅ Tested (Docker)
Windows (Native)	✅ Tested
Windows (WSL2)	✅ Tested

Test Plan

• macOS: Verify notification appears after 20+ second task
• macOS: Verify permission prompt triggers notification
• macOS: Verify /notifier command works correctly
• Linux: Test with notify-send (Docker)
• Windows Native: Test with PowerShell toast notifications
• Windows WSL2: Test with PowerShell toast notifications

🤖 Generated with Claude Code