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>

.gitignore

@@ -0,0 +1,32 @@
+# Rust / Cargo
+/target/
+Cargo.lock
+
+# Editor and IDE
+.vscode/
+.idea/
+*.iml
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Environment / secrets
+.env
+.env.*
+
+# Build artifacts and packages
+*.deb
+*.rpm
+*.tar.gz
+*.zip
+
+# Logs
+*.log
+
+# Personal scratch notes (tracked docs live in docs/ and are NOT ignored)
+*.local.md
+/scratch/