Rebrand: Info-physics → Intention engine

Core concept:
- Traditional engines simulate motion
- MDS simulates meaning
- Gravity comes from similarity
- Motion emerges from intent

Updates:
- README.npm.md: Philosophical quote + intention engine sections
- package.json: New description + keywords
- Philosophy: Forces = intent × proximity

This better captures what MDS truly is: an engine where materials
with essence naturally organize based on meaning, not physics.