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>

editor/Cargo.toml

@@ -0,0 +1,34 @@
+[package]
+name = "oxide-editor"
+description = "Oxide Engine — in-engine editor"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+rust-version.workspace = true
+
+[[bin]]
+name = "oxide-editor"
+path = "src/main.rs"
+
+[dependencies]
+oxide-engine = { path = "../engine" }
+oxide-physics = { path = "../physics" }
+oxide-script = { path = "../script" }
+log.workspace = true
+env_logger.workspace = true
+anyhow.workspace = true
+egui.workspace = true
+egui-wgpu.workspace = true
+egui-winit.workspace = true
+egui_dock.workspace = true
+# Editor preferences file I/O reads/writes the same RON shape `Settings`
+# exports; the engine already pulls `ron` in, the editor now does too.
+ron.workspace = true
+
+# PTY-backed terminal panel (Stage 10): run interactive/TUI programs — shells,
+# REPLs, and AI-agent CLIs like `claude` — inside the editor. `portable-pty`
+# opens a real pseudo-terminal (cross-platform: Linux now, Windows later);
+# `vt100` parses the program's byte stream into a screen grid the panel renders.
+portable-pty = "0.9"
+vt100 = "0.16"