Gracefully handle invalid characters in PATH.

[cincuranet]

Fixes #2293.

[Copilot]

Pull Request Overview

This PR adds graceful handling for invalid characters or paths in the PATH environment variable by wrapping Path.Combine in a try-catch block to prevent exceptions when processing potentially malformed PATH entries.

• Replaced direct Path.Combine call with a new TryCombinePaths helper method that handles exceptions
• Added a local static helper function to safely combine paths and return success/failure status

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