Extract independent MIT Mortar kit and contribution workflow

tsconfig.playground.json

@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "jsx": "react-jsx",
+    "strict": true,
+    "skipLibCheck": true,
+    "resolveJsonModule": true,
+    "allowSyntheticDefaultImports": true,
+    "types": ["vite/client"]
+  },
+  "include": ["playground", "previews", "src"]
+}