fix: improve Windows discovery and npm launcher support

[OrdinarySF]

Summary

• resolve JetBrains config directories across macOS, Windows, and Linux so discovery can read MCP settings reliably
• probe MCP endpoints via both localhost and 127.0.0.1, preserving the detected host and transport for Windows-friendly auto-discovery
• normalize Windows project paths for IDE matching and improve multi-IDE error output with project labels
• replace the shell-only npm bin entry with a JS Node launcher so global npm installs work on Windows
• add regression coverage for Windows discovery, path matching, and npm packaging behavior

Testing

• bun test
• bun run build:npm

Closes #1