Add mapping mode for physics props

[IsaacThoman]

Summary

Adds an in-game Mapper Mode for authoring map physics props:

• Enables mapper mode with ?mode=mapping, ?mapping=1, #mapping, or F7.
• Adds a no-clip/free-fly authoring overlay that can ray-select named static GLB nodes.
• Lets players map selected static nodes to configurable physics props, including model URL, scale, velocity, angular velocity, doPhysics, playersCollide, and health.
• Exports replacement map JSON with staticPropExclusions plus props, so selected static GLB nodes can be removed from static collision/rendering and represented as physics props instead.
• Teaches client and server static collision/physics loaders to skip excluded GLB node names.

Validation

• deno task allchecks
• Browser smoke test on http://localhost:4178/?mode=mapping:
  • confirmed current rebuilt bundle loaded on a fresh origin
  • confirmed map rendered
  • selected static node Cube004 from the game view
  • added it as a banana physics prop
  • changed exported health, velocity, and player-collision settings
  • verified exported JSON contains staticPropExclusions: ["Cube004"] and a configured /models/simplified_banana_1.glb prop
• Server compatibility check with MapData.fromJSON(...) and PhysicsEngine.create("deathmatch_1", ["Cube004"])

Notes

The in-app browser had a stale service worker on port 4177, so browser validation was performed on a clean localhost origin at port 4178.