Update version to 1.0.1; enhance PHP 8.3 compatibility

[soderlind]

This pull request releases version 1.0.1 of the Custom Document Folder plugin, focusing on modernizing the codebase for PHP 8.3 strict typing compliance and improving developer experience. The update introduces typed properties, method signatures, improved PHPDoc annotations, and a plugin activation hook to ensure default settings are initialized. All tests are passing, confirming the stability of these changes.

Code modernization and type safety:

• Added PHP 8.3 typed properties (array, string) to all class properties for stricter type enforcement. [1] [2]
• Added return type declarations (:void, :array, :string) to all methods, and parameter type declarations (mixed, string) across the codebase. [1] [2]
• Improved PHPDoc annotations with generic types (e.g., array<string>) for better IDE support and documentation. [1] [2]
• Achieved full PHP 8.3 strict typing compliance throughout the plugin. [1] [2]

Plugin functionality and stability:

• Added a plugin activation hook to ensure default settings are created when the plugin is activated, improving reliability for new installs. [1] [2]

Documentation and versioning:

• Updated CHANGELOG.md, readme.txt, and plugin headers to reflect version 1.0.1 and document all new features, improvements, and upgrade instructions. [1] [2] [3] [4] [5] [6]
• Confirmed all 7 tests are passing (21 assertions), ensuring code quality and stability.

No changes to plugin behavior or features outside of type safety and activation logic were introduced in this release.