Improve Scoop custom path detection

[breshinotestachegira]

Summary

This PR improves Scoop detection for users with non-default or customized Scoop installations.

Changes

• detect Scoop from PATH, not only from SCOOP / SCOOP_GLOBAL environment variables
• inspect Scoop config.json candidates and apply root_path / global_path overrides when present
• keep the existing default-path behavior as fallback

Why

Some users install Scoop in custom locations or rely on PATH/shims instead of explicit environment variables. In those setups, detection can be incomplete or fail even though Scoop is installed and working.

This change makes detection more tolerant of real-world Scoop setups without changing the default behavior for standard installs.

Verification

• local build still completes successfully
• Scoop path resolution now works when Scoop is available through PATH
• custom Scoop config overrides are recognized when present

Closes #887