Make composite effects conform to the render and update contracts

[jsulpis]

Problem

CompositeEffectPass is typed as an EffectPass without fragment and vertex, so it promises the standard pass contract. Its implementation does not fulfill key parts of that contract:

• The inherited API advertises render({ target, clear }), but composite render() accepts no options and ignores overrides.
• onUpdated is typed as updates to the composite uniform object, but it forwards child-pass updates instead.
• Direct writes to composite.uniforms do not use a reactive proxy and emit no update event.
• Callback hooks use any despite the generic public type.

Impact

Consumers cannot write generic code over EffectPass | CompositeEffectPass safely. Render target overrides and clear behavior can fail silently, while render-on-demand code gets misleading update events. These inconsistencies will make nested composites and graph-level tooling difficult to add compatibly.

Relevant code

• lib/src/passes/compositeEffectPass.ts:20-43,55-88
• lib/src/passes/renderPass.ts:113-153,241-288

Proposed API decision

Create and export a shared render-options type:

type RenderOptions = {
  target?: RenderTarget | null;
  clear?: boolean;
};

Every renderable pass should implement render(options?: RenderOptions): void.

For composites:

• Apply target to the final output child.
• Define and document whether clear applies only to that child or to each child.
• Make composite uniforms reactive, with onUpdated emitting only composite-uniform changes.
• If child changes need to be observable, expose a separate explicitly typed callback that identifies the child pass.

Acceptance criteria

• Composite render accepts and implements shared render options.
• Target override and clear semantics are documented and tested.
• onUpdated accurately represents composite uniform mutations.
• Child-pass updates use a separate callback or are deliberately not exposed.
• No public any is required for composite hooks.
• A generic function accepting any renderable pass can call render(options) safely.