Support legacy physics API in Carbide

[simsaens]

Feature description

Carbide offers physics2d and physics3d

We should offer the standard legacy physics API as a wrapper around physics2d

[simsaens]

Physics (2D)

Feature	Legacy API	Modern API	Status
World access	physics.* singleton world	physics2d.world() instance	⚠️ No default world or auto-step
Body creation	physics.body(shapeType, ...)	world:body(type, x, y) then body:circle/box/polygon	⚠️ Wrapper needed
Shape types	CIRCLE, POLYGON, CHAIN, EDGE	circle, box, polygon	⚠️ Chain/edge not bound
Body position	body.x, body.y, body.position	body.position	⚠️ Rename or proxy
Body angle	body.angle (degrees)	body.rotation (degrees)	⚠️ Rename
Body material	body.friction, body.restitution, body.density	collider.friction, collider.restitution, collider.density	⚠️ Proxy to colliders
Collision filters	body.categories = {1,2} / body.mask = {1..16}	collider.category / collider.mask bitfield	⚠️ Convert list ↔ bitfield
Active flag	body.active	body.enabled	⚠️ Rename
Body queries	body:testPoint(), body:testOverlap()	No body-level query helpers	❌ Missing
Contacts	Global collide(contact) with BEGAN/CHANGED/ENDED and impulse/points	Per-body callbacks with physics2d.contact (no state/impulses)	❌ Missing fields + global hook
Joints	physics.joint(type, ...) with REVOLUTE/PRISMATIC/DISTANCE/WELD/ROPE	body:hinge/slider/distance (weld/rope not bound)	⚠️ Mapping + missing joints
Raycasts	physics.raycast(start, end, ...) / raycastAll	world:raycast(origin, dir, distance[,mask])	⚠️ Wrapper + raycastAll binding
AABB query	physics.queryAABB(lowerLeft, upperRight, ...)	world:queryBox(origin, size[,mask]) (returns collider)	⚠️ Wrapper + body result
Simulation settings	physics.gravity, physics.iterations, physics.timeStep, physics.pause/resume, physics.pixelToMeterRatio, physics.continuous	world.gravity, world:step(deltaTime)	❌ Missing settings in Lua

Notes:

• Legacy units are pixels with a configurable physics.pixelToMeterRatio; Carbide physics2d currently exposes raw Box2D units with no scaling hook.
• Legacy physics.raycast returns {body, point, normal, fraction}; Carbide returns rayHit with a collider (body can be derived from collider.body).