* feat(physics): add interactive cloth and 2D fluid solvers
Extend the Physics module with Verlet cloth (pin/grab) and
double-density-relaxation fluid (emit/interact), plus Squirrel
bindings, tests, docs, and an examples/softbody demo.
Co-authored-by: 西风逍遥游 <sunxfancy@gmail.com>
* fix(physics): improve cloth constraint solve and softbody tests
Apply full distance correction when one cloth particle is pinned, and
tighten unit tests around pin hold, free-fall, grab, and fluid behavior.
Co-authored-by: 西风逍遥游 <sunxfancy@gmail.com>
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Co-authored-by: Cursor Agent <cursoragent@cursor.com>
