Align with Pixi v8: Filter[] union, WebGLRenderer narrow, ImageLike

Four sites where Pixi v8's stricter typing tripped tsgo:

- AvatarImage: container.filters is typed as 'readonly Filter[] | null'
  in v8 (no longer a single-Filter union). The old fallback branch
  'else container.filters = [container.filters, …]' tried to treat a
  readonly array as a single Filter; collapsed to the array-spread
  path which now covers both undefined and non-empty cases. Added
  Filter to the pixi.js import.
- FurnitureBadgeDisplayVisualization.updateSprite() had a 4-arg
  override (sprite, asset, scale, layerId) of the parent's 2-arg
  signature (scale, layerId). The sprite/asset were never used from
  the parameters — the body only mutated 'sprite'. Refactored to
  fetch the sprite via this.getSprite(layerId) inside the override
  body so the signature matches the base.
- ExtendedSprite: 'renderer.gl' / 'glRenderTarget.resolveTargetFramebuffer'
  exist only on WebGLRenderer / GlRenderTarget (not the WebGPU
  variants). The runtime check 'renderer.type === RendererType.WEBGL'
  guarantees this; cast at the boundary to satisfy the typechecker.
- TextureUtils.generateImage: Pixi v8's Extractor.image() returns the
  union ImageLike (HTMLCanvasElement | HTMLImageElement); the public
  signature promises HTMLImageElement. Cast at return — the Pixi
  default backend returns HTMLImageElement here.

packages/utils/src/TextureUtils.ts

@@ -28,7 +28,7 @@ export class TextureUtils
 
         try
         {
-            return await this.getExtractor().image(options);
+            return await this.getExtractor().image(options) as HTMLImageElement;
         }
         catch(e)
         {