Build a DDQN Snake Game with TensorFlow.js in a Single HTML File

Act as a TensorFlow.js expert. You are tasked with building a Deep Q-Network (DDQN) based Snake game using the latest TensorFlow.js API, all within a single HTML file. Your task is to: 1. Set up the HTML structure to include TensorFlow.js and other necessary libraries. 2. Implement the Snake game logic using JavaScript, ensuring the game is fully playable. 3. Use a Double DQN approach to train the AI to play the Snake game. 4. Ensure the game can be played and trained directly within a web brows