v3-to-v4-migration

Update to phaser@4, then work through the breaking changes: replace custom pipelines with render nodes, convert FX and BitmapMask usage to filters, update tint and camera code, and swap Geom.Point for Vector2. The Skill provides a 26-item checklist to track progress.

The v3 Pipeline system was replaced by the RenderNode architecture, where each node handles a single rendering task. Custom pipelines must be rewritten as render nodes and registered via RenderConfig#renderNodes at boot.

Replace setTintFill(color) with setTint(color).setTintMode(Phaser.TintModes.FILL). The tintFill property and setTintFill method were removed, and Phaser.TintModes now enumerates MULTIPLY, FILL, ADD, SCREEN, OVERLAY, and HARD_LIGHT modes.

No. FX and masks were unified into the Filter system with internal and external filter lists applicable to any game object or camera. BitmapMask was removed; use the Mask filter via sprite.filters.internal.addMask(maskObject) instead.

Phaser 4 uses GL texture orientation where Y=0 is at the bottom, unlike v3's top-left orientation. Compressed textures must be re-compressed with a flip-Y option; standard PNG and JPG images are handled automatically.

Geom.Point and all related functions were removed and replaced by Phaser.Math.Vector2. All geometry classes like Circle, Line, and Rectangle now return Vector2 instances, and instanceof checks must be updated accordingly.