Neon Flow Grid Snake Prompt

I want you to act as an expert HTML5 Canvas game developer. Your task is to write a complete, playable SINGLE FILE (index.html) game based on a modernized snake mechanic.

GAME SPEC:

Title: Cyber Grid Link

Core mechanic: Control a snake made of chained vector particles on a shifting grid environment.

Goal: Collect glowing energy matrix crystals to grow the link chain while dodging moving firewall barriers.

TECH REQUIREMENTS:

Single file: Pure vanilla JS inside one HTML document, zero external libraries, zero asset downloads.

Rendering: HTML5 2D Canvas with requestAnimationFrame game loop. Smooth LERP interpolation for snake segment movement to create a fluid, organic motion rather than classic blocky steps.

Controls: Arrow keys or WASD for absolute directional steering.

Design style: Cyberpunk dark theme. The grid must warp slightly near the snake's head using localized coordinate displacement. The snake chain features a pulsing gradient texture.