Create a portable shimmer effect component inspired by the shared shimer.mp4 video:
- Use vanilla WebGL with embedded vertex and fragment shaders.
- Render a dark, grainy background with a strict grid of small uniform squares (pixel-square cells regardless of stage aspect).
- Most squares stay still at low ambient brightness; a sparse subset blinks very gently.
- On hover, leave a bright trail of lit squares that follows the cursor with a smoothed lag.
- The cursor head stays bright while stationary; the trailing streak fades to zero in ~500ms.
- Drive the trail by a 64-slot CPU ring buffer (xy + age) uploaded as a uniform array.
- Keep the effect behind arbitrary children so it can be pasted into any React site.
- Avoid external animation or WebGL libraries.
- Respect prefers-reduced-motion by rendering hover feedback without continuous motion.
- Include a non-WebGL fallback so the component still displays a dotted background.