011eb48ffd
Replace platform-specific 'which'/'where' commands with cross-platform Bun.which() API to fix Windows compatibility issues and simplify code. Fixes: - #1027: Comment-checker binary crashes on Windows (missing 'check' subcommand) - #1036: Session-notification listens to non-existent events - #1033: Infinite loop in session notifications - #599: Doctor incorrectly reports OpenCode as not installed on Windows - #1005: PowerShell path detection corruption on Windows Changes: - Use Bun.which() instead of spawning 'which'/'where' commands - Add 'check' subcommand to comment-checker invocation - Remove non-existent event listeners (session.updated, message.created) - Prevent notification commands from resetting their own state - Fix edge case: clear notifiedSessions if activity occurs during notification All changes are cross-platform compatible and tested on Windows/Linux/macOS.