feat(web): add browser build for TDK Pinball

Expose the existing Macroquad game as a static WASM website while preserving
native desktop behavior. Native-only simulation/file-export code and the
per-user filesystem save path are now separated from the browser build.

The browser version uses a small WASM-only storage support crate and a
Macroquad-compatible JavaScript plugin to persist the same JSON settings and
high scores in localStorage. Browser audio decoding starts in an owned
background coroutine so the game can render its original loading/attract
screens while the embedded sounds finish loading. The checked-in web bundle
contains the optimized WASM, centered black HTML shell, and build/serve
instructions.

Test Plan:
- `just test` -- passed, 135 tests
- `just clippy` -- passed
- `cargo clippy --target wasm32-unknown-unknown -- -D warnings` -- passed
- `cargo +nightly fmt --check` and web-storage format check -- passed
- `just web-build` -- passed; packaged WASM matches the production artifact
- Browser smoke test at `http://127.0.0.1:8000/` -- rendered the centered
  game, started gameplay, opened settings, and restored a changed language
  from browser storage in a fresh page with no runtime errors

tdkpin-rs/README.md

@@ -31,6 +31,19 @@ development packages are also required (X11, OpenGL, and ALSA). Windows needs
 no extra runtime installation; macOS builds with the normal Apple developer
 command-line tools.
 
+## Browser version
+
+Build and serve the WASM website locally with:
+
+```sh
+just web-serve
+```
+
+Then open <http://127.0.0.1:8000/>. The browser build keeps the original
+640x460 presentation centered on a black page and stores settings and high
+scores in browser storage. See [web/README.md](web/README.md) for the static
+bundle details.
+
 ## Deterministic mechanics validation
 
 Named scenarios can be advanced without waiting in real time. The simulator