🐛 Fixes

• Fixed deprecated inventory closing logic in the withdraw anvil controller, resolving issues with banknote inventory interactions.
• Added missing null checks for online players in economy commands.
• Fixed the Java 21 build configuration, improving build reliability and compatibility with the current project environment.

🧩 Other Notable Changes

• Improved compatibility with current Paper API changes.
• Improved overall code maintainability by replacing deprecated API usage.