### Added
- **Flexible Windows shell configuration**: The bash tool now supports multiple shell sources beyond Git Bash. Resolution order: (1) custom `shellPath` in settings.json, (2) Git Bash in standard locations, (3) any bash.exe on PATH. This enables Cygwin, MSYS2, and other bash environments. Configure with `~/.pi/agent/settings.json`: `{"shellPath": "C:\\cygwin64\\bin\\bash.exe"}`.
### Fixed
- **Windows binary detection**: Fixed Bun compiled binary detection on Windows by checking for URL-encoded `%7EBUN` in addition to `$bunfs` and `~BUN` in `import.meta.url`. This ensures the binary correctly locates supporting files (package.json, themes, etc.) next to the executable.