A corgi on a treadmill

Build a single self-contained HTML file with a 3D scene made in Three.js (you may load Three.js from a CDN).

The scene: a corgi running on a treadmill in a small home gym. The corgi's four legs should move in a believable running cycle, its body should bounce, its ears and tail should react to the motion, and the treadmill belt should visibly move under its paws. Give the room some character: a window, a few weights, a water bowl.

Rules:
- The animation starts on its own and loops forever. No interaction, no controls, no buttons.
- No text, labels or UI on screen.
- The scene fills the whole browser window and is framed for a square viewport, with the corgi clearly visible in the middle.
- Everything is built in code. No external images, models or textures.

Paste it into any model and see what you get.