Implements custom regex copy targets and reordering

[Moyf]

This update significantly enhances the plugin's copy functionality by allowing users to define and prioritize their own regex-based copy targets.

• Custom Regex Matchers: Users can now create custom copy rules using regular expressions, defining the pattern, flags, and capture group. This enables copying of content within arbitrary syntax not covered by built-in options.
• Reorderable Copy Targets: Both built-in and newly created custom copy targets can now be reordered in the plugin settings. This allows users to define the priority of matching, ensuring the desired content is copied when multiple rules apply.
• AI Prompt Helper: A new helper has been added to the custom matcher configuration, providing a prompt to assist users in generating regular expressions with AI tools.
• Refactored Matching Logic: The core copy matching logic has been extracted into a dedicated module, improving code organization, maintainability, and testability.
• Enhanced Settings UI: The plugin settings have been updated to provide an intuitive drag-and-drop interface for reordering targets and a comprehensive configuration panel for custom regex matchers, including real-time regex validation.