Production Architecture and Reproducible Project Skeleton

Pin Godot 4.7.1, the compatible godot-rust revision, and the Rust toolchain in reproducible project configuration.

Partition the workspace into pure Rust engine, compiled content, Godot adapter, and presentation-asset components.

Enforce a dependency direction that prevents the engine and content components from importing Godot APIs.

Register a Rust extension entry point and a root Godot controller without using GDScript.

Define feature flags that isolate desktop-only and web-specific integration code.

Represent requests to the engine as a typed command enum.

Represent engine results as a typed event enum.

Add smoke tests that independently verify the pure Rust engine and its Godot extension loading boundary.