FXLayer Pixi Layer

[1brucben]

This pull request refactors the FX (effects) rendering system in the client graphics codebase to use PixiJS for all FX rendering, replacing direct Canvas2D drawing. The changes introduce a new architecture where FX are represented as Pixi display objects, managed in a dedicated FxLayer with proper positioning and lifecycle management. This enables more advanced visual effects and paves the way for future improvements in performance and maintainability.

Major migration to PixiJS for FX rendering:

• Refactored the Fx interface and all FX classes (SpriteFx, FadeFx, ShockwaveFx, UnitExplosionFx) to use PixiJS containers and rendering primitives instead of Canvas2D methods. Each FX now exposes a getDisplayObject() method returning a Pixi container for rendering. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
• Updated the AnimatedSpriteLoader to provide PixiJS textures and configuration for FX sprites, supporting colored and regular animated sprites. [1] [2]

New FX layer architecture:

• Implemented a new FxLayer that manages all FX as PixiJS display objects, including initialization of a PixiJS renderer and stage, and mapping FX to world coordinates for correct screen positioning. Added logic to handle window resizing and FX lifecycle. [1] [2] [3] [4]

Integration and API changes:

• Changed the creation and management of FX in game event handlers to use the new FxLayer API, passing world coordinates and handling FX addition/removal via PixiJS containers. [1] [2]
• Updated the GameRenderer to instantiate FxLayer with the required TransformHandler and adjusted the layer rendering loop to accommodate the new rendering approach. [1] [2]

These changes collectively modernize the FX rendering pipeline, making it more extensible and visually capable.