feat: add custom macOS binary search paths

[tomsquest]

Fixes #1

[Copilot]

Pull Request Overview

This PR adds support for custom binary search paths on macOS to improve binary discovery. The implementation extends the PATH environment variable with additional macOS-specific directories before searching for binaries.

Key changes:

• Enhanced binary search to include custom macOS paths like ~/.local/bin and JetBrains Toolbox scripts directory
• Modified the _find_binary method to use an extended PATH for binary discovery
• Added OS import for environment variable access

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