refactor(wrapEffect): split out of util.tsx, support ref as a prop

[kvvasuu]

Stacked PR 2/6 — part of a split of #350 .
← based on #351 · → followed by #353

Pulls wrapEffect out of the general util grab-bag into its own module, and lets generated effect components accept ref as a regular prop (React 19) instead of having no ref support at all - previously none of the wrapEffect-based effects (Bloom, Vignette, HueSaturation, etc.) could be given a ref. Autofocus gets the same ref-as-prop treatment directly (it doesn't go through wrapEffect).

Also fixes two related wrapEffect bugs:

• The args memo fingerprinted props with JSON.stringify, which threw on circular references (textures, refs, and other three.js objects commonly hold one) - two independent reports (fixes cyclic object value error in Scanline when using useRef #333, fixes circular structure to JSON --> starting at object with constructor #334) hit this on ordinary usage. Swapped in a cycle-safe stringify.
• That fingerprint also called JSON.stringify's implicit toJSON, so THREE.Texture.toJSON() was re-encoding the whole image to a base64 data URL on every render just to compute a value that got discarded
  • measured ~39ms for a 512x512 texture. Fingerprinting now walks own properties directly and collapses typed arrays/buffers to an identity token instead.
• ref itself wasn't destructured out of props, so it leaked into that same fingerprint; once mounted, ref.current pointed at the effect instance, so every render after the first fingerprinted a different value and silently rebuilt the instance in a loop.

Adds a shared test harness (test-utils.tsx) used by this and later commits' test suites.