Add counter example; fix configuration

examples/accident-counter/src/counter.tsx

@@ -0,0 +1,42 @@
+import React, { useReducer, useEffect } from 'react';
+import { reducer } from './reducer';
+
+export const Counter = () => {
+  const [state, dispatch] = useReducer(reducer, { count: 0 });
+  const unit = state.count === 1 ? 'day' : 'days';
+
+  useEffect(() => {
+    window.document.title = `${state.count} ${unit}`;
+  }, [state.count]);
+
+  return (
+    <div className="p-8 space-y-8 text-center bg-white border rounded-md shadow-lg border-slate-400">
+      <div className="space-y-4">
+        <div data-test-id="counter-count" className="font-semibold text-8xl">
+          {state.count}
+        </div>
+        <p>
+          <span data-test-id="counter-unit">{unit}</span> since the last
+          accident.
+        </p>
+      </div>
+      <div className="flex gap-4">
+        <button onClick={() => dispatch({ type: 'increment' })}>
+          Increment
+        </button>
+        <button
+          onClick={() => dispatch({ type: 'decrement' })}
+          disabled={state.count === 0}
+        >
+          Decrement
+        </button>
+        <button
+          onClick={() => dispatch({ type: 'reset' })}
+          disabled={state.count === 0}
+        >
+          Reset
+        </button>
+      </div>
+    </div>
+  );
+};