Import Oxide engine (Stages 0–10) under MIT license

Full project snapshot migrated to new Gitea remote without history:
engine, editor, physics, script, examples, tests, docs, and assets.
Relicensed from GPLv3 to MIT and updated repo URLs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

physics/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "oxide-physics"
+description = "Oxide 3D game engine — physics module (rapier3d)"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+oxide-engine = { path = "../engine" }
+glam.workspace = true
+hecs.workspace = true
+serde.workspace = true
+ron.workspace = true
+thiserror.workspace = true
+log.workspace = true
+
+# The physics backend. rapier3d bundles its own nalgebra (`rapier3d::na`); the
+# module converts at the boundary so the rest of the engine stays on `glam`.
+rapier3d = "0.33"
+
+[dev-dependencies]
+ron.workspace = true