separate out renderer crate (#13)

* add keyboard handler

* some cleanup

* add l key binding

* Fix WASM shared memory generation for Rust nightly 2025-10-20+

Add explicit linker flags for shared memory generation after Rust PR #147225
removed automatic flags with +atomics. This fixes DataCloneError when sharing
memory with workers.

Changes:
- Add --shared-memory, --max-memory, --import-memory flags
- Export TLS symbols: __wasm_init_tls, __tls_size, __tls_align, __tls_base
- Update both Cargo.toml and package.json build scripts

Amp-Thread-ID: https://ampcode.com/threads/T-41d99b69-5754-4fdf-b06e-a46343fa7485
Co-authored-by: Amp <amp@ampcode.com>

* add a level-editor crate

* remove redundant worker setup

* simplify app setup

* add SceneBuilder

* separate out default scene implementation in a crate

* define default method for MeshBuilder

---------

Co-authored-by: Amp <amp@ampcode.com>

AGENTS.md

@@ -16,3 +16,4 @@
 - **WGSL shaders**: Keep binding names aligned with Rust bind group layouts
 - **JavaScript/TypeScript**: Format with prettier defaults
 - **Comments**: Add documentation comments for public APIs using `///`
+- **Logging**: Use `log::info!`, `log::error!`, etc. from the log crate, not `println!`