Add Snake and Commits to Tools

[dahan8473]

Adds snake-and-commits to the Tools section.

It turns your contribution graph into a real, self-playing game of Snake: BFS pathfinding to hunt commit cells, self-collision avoidance, tail-chasing when boxed in, and it grows one segment per cell eaten while auto-tuning its length to clear the whole board. Pure animated SVG (CSS, no JavaScript), one standard-library Python file with zero dependencies, and it ships as a drop-in GitHub Action. MIT licensed.

Guidelines checklist:

• Individual PR for a single suggestion
• Name starts with a capital
• Spelling and grammar checked
• No trailing whitespace