make workspace build and test reproducibly

- add Gitea sparse registry config for rmath
- commit Cargo.lock
- add default-members so host tests skip GTK/wasm frontends
- fix checkers example to use DraughtsBoard::get
- add README with prerequisites and per-frontend commands
- add Gitea CI workflow (core, wasm, wasm4, MSRV)
- fix repository metadata and stop tracking generated wasm dist

rdraught-wasm/dist/index.html

@@ -1,27 +0,0 @@
-<!DOCTYPE html>
-<html>
-
-<head>
-  <meta content="text/html;charset=utf-8" http-equiv="Content-Type" />
-  <style>
-    body {
-      margin: 0px;
-    }
-  </style>
-<link rel="modulepreload" href="/rdraught-wasm-1d648b9090e33d1f.js" crossorigin="anonymous" integrity="sha384-T7IqpVlu6X9Lrf6TI9E2mHL6bPl2B4DHWKUGmbtsfGa1QSmnJBFB8IRe7clx0yWb"><link rel="preload" href="/rdraught-wasm-1d648b9090e33d1f_bg.wasm" crossorigin="anonymous" integrity="sha384-v+/7HPNa68RnAHRmXFFl7L7bUCWjUJnc8AGKHfn6l5NJiPANQ7yqdGRb+abf1wyh" as="fetch" type="application/wasm"></head>
-
-<body>
-
-<script type="module">
-import init, * as bindings from '/rdraught-wasm-1d648b9090e33d1f.js';
-const wasm = await init({ module_or_path: '/rdraught-wasm-1d648b9090e33d1f_bg.wasm' });
-
-
-window.wasmBindings = bindings;
-
-
-dispatchEvent(new CustomEvent("TrunkApplicationStarted", {detail: {wasm}}));
-
-</script></body>
-
-</html>