feat: add gameplay assists and variant generator

tests/components/digitCompletionBar.test.tsx

@@ -0,0 +1,32 @@
+import { render, screen } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+import { DigitCompletionBar } from "../../src/components/DigitCompletionBar";
+import { digitCompletions } from "../../src/state/gameplayHelpers";
+
+describe("digit completion bar", () => {
+  it("renders complete digits muted and excess digits as overdone", () => {
+    const values = new Array<number>(81).fill(0);
+    values.fill(1, 0, 9);
+    values.fill(2, 9, 19);
+
+    render(
+      <DigitCompletionBar
+        size={9}
+        completions={digitCompletions(9, values)}
+        highlightedDigit={null}
+        highlightingEnabled
+        onHighlight={vi.fn()}
+      />,
+    );
+
+    expect(
+      screen.getByRole("button", { name: /Digit 1: complete/u }),
+    ).toHaveClass("is-done");
+    expect(
+      screen.getByRole("button", { name: /Digit 2: overdone by 1/u }),
+    ).toHaveClass("is-overdone");
+    expect(
+      screen.getByRole("button", { name: /Digit 3: 9 remaining/u }),
+    ).toHaveClass("is-undone");
+  });
+});