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>

.cargo/config.toml

@@ -1,3 +1,15 @@
 [build]
 target = "wasm32-unknown-unknown"
-rustflags = '-Ctarget-feature=+atomics,+bulk-memory,+mutable-globals'
+rustflags = [
+    '-Ctarget-feature=+atomics,+bulk-memory,+mutable-globals',
+    '-Clink-args=--shared-memory',
+    '-Clink-args=--max-memory=1073741824',
+    '-Clink-args=--import-memory',
+    '-Clink-args=--export=__wasm_init_tls',
+    '-Clink-args=--export=__tls_size',
+    '-Clink-args=--export=__tls_align',
+    '-Clink-args=--export=__tls_base',
+]
+
+[unstable]
+build-std = ['std', 'panic_abort']