Refactor and Replace Inventory GUI Framework with Custom DSL-Based System

[ammodev]

This patch represents a major architectural overhaul of the Surf API's inventory GUI system for the Bukkit platform. The update fully replaces the previously used external InventoryFramework dependency with a custom-built GUI framework tailored for extensibility, type safety, and integration into Kotlin-based DSL workflows.

Key highlights of this update include:

• Removal of Legacy System:
  The previous SurfGui, SinglePlayerGui, and all associated InventoryFramework-based DSLs and components (e.g., SurfGuiItem, SubmitItemPane, slot.kt, etc.) have been entirely removed, eliminating third-party dependency coupling and outdated design patterns.

• Introduction of New GUI Abstractions:
  A new GUI base class (Gui) and its extension NamedGui provide the foundation for all inventory interfaces. These manage lifecycle, rendering, event delegation, and player-specific behavior like parent navigation and update tracking.

• DSL Enhancements:
  The patch introduces Kotlin-based builders (menu, playerMenu, childMenu, etc.) that allow developers to construct complex inventories using declarative and readable syntax. It supports typed pane creation via staticPane, paginatedPane, and pagingButtons.

• Modular Pane System:
  New pane types were added, including:

  • StaticPane – for fixed layouts.
  • PaginatedPane – with integrated page navigation.
  • OutlinePane – for decorative or border-style layouts.
    Each pane supports composability and fine-grained item placement via Slot utilities.

• Powerful GUI Items:
  A new GuiItem abstraction supports UUID-based tracking, permission filtering, visibility toggling, and robust event handling with improved error logging. UpdatableGuiItem introduces item-level reactivity by enabling live updates inside GUIs.

• Internal Utilities:
  Supporting classes like InventoryComponent, PlayerInventoryCache, and Pattern, Rotatable, Flippable utilities enhance layout logic, slot control, and transformation of inventory designs.

• Improved Event Handling:
  All inventory events (clicks, drags, closes) are now internally routed through lambda-based callback systems with isolated error management and stack trace logging.

• Versioning and Cleanup:
  Version bumped to 1.21.4-2.16.0-SNAPSHOT. Numerous test files, configuration modules, and legacy Kotlin/Java files have been cleaned up or adapted to the new system, ensuring a consistent and streamlined codebase.

This update sets the stage for future extensibility, including custom inventory types, animation support, and advanced GUI tooling without relying on external GUI frameworks. It reflects a deep integration of Kotlin DSL design and a scalable internal GUI engine aligned with Minecraft plugin development best practices.