Mirror Tracing Test

Create a mirror tracing brain test using Three.js. Build a 3D desk scene with a physical mirror that reflects a paper with a star outline via render-to-texture. The player traces the star channel by moving the mouse on the mirrored surface — horizontal movement is reversed. Track boundary errors, channel accuracy percentage, and completion time. Use an orthographic camera for the mirror's top-down paper view and a perspective camera for the main scene. Include a pencil that follows the cursor on the paper, a green start dot, colored trail (green=in bounds, red=out), segment-based progress tracking, and a letter grade result screen (S through F). Dark minimal aesthetic with IBM Plex fonts.