Karta PlayerContract

• Fix Slanted GUI Text: All text in the contract GUIs is now rendered without italics for a cleaner look.
• Separate Item Amount: In the personal contract view, the item amount is now displayed on a separate line below the item name for better readability.
• Add Contract Cancellation: Players can now cancel contracts they have created by right-clicking on them in the /contract inv GUI, as long as the contract has not been accepted yet.
• Capitalize Success Message: The item name in the contract creation success message is now properly capitalized (e.g., "Diamond Sword" instead of "DIAMOND_SWORD").
• Update Documentation: The README.md has been updated to reflect these new features and improvements.

• Fix missing message

• Added all missing GUI-related messages to src/main/resources/message.yml for both ContractGUI and PlayerInventoryGUI.
• Refactored ContractGUI.java to use the message manager for its navigation buttons.
• Refactored the entire PlayerInventoryGUI.java to remove hardcoded strings and use the ConfigManager for all displayed text, making it consistent with the rest of the plugin.
• Added a getRawMessage method to ConfigManager.java to safely retrieve raw string values for use in placeholders, which was necessary to fix a compilation error introduced during the refactoring.

• Changed the main command to /kartaplayercontract with aliases /playercontract and /contract as requested by the user.
• Made the admin permission node configurable in config.yml.
• Added a /contract reload alias for the admin reload command for easier use.
• Corrected the command registration in the main plugin class to reflect the changes.

Initiate and Publish Karta PlayerContract