write a complete, playable SINGLE FILE (index.html) game based on a modernized snake mechanic.
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.
