Fix import hook - #107

Pull Request Overview

This PR refactors the import hook system to improve code organization and error handling. It modernizes the code with type annotations and replaces the single-spec finding approach with an iterator-based approach that can handle multiple module specs.

• Adds modern Python type annotations and imports
• Refactors spec finding logic to use an iterator pattern for better error handling
• Improves code structure by removing outdated comments and simplifying class definitions

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