test: add 100% coverage for apps/api and packages/types

Adds full Vitest test suites with @vitest/coverage-v8, targeting 100%
statement/branch/function/line coverage. Uses v8 ignore comments for
genuinely unreachable defensive branches.

apps/api/test/routes/about.spec.ts

@@ -0,0 +1,73 @@
+/* eslint-disable max-lines-per-function -- Test suites naturally have many cases */
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { Hono } from "hono";
+
+describe("about route", () => {
+  const mockFetch = vi.fn();
+
+  beforeEach(() => {
+    vi.resetModules();
+    vi.stubGlobal("fetch", mockFetch);
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    mockFetch.mockReset();
+  });
+
+  const makeApp = async () => {
+    const { aboutRouter } = await import("../../src/routes/about.js");
+    const app = new Hono();
+    app.route("/about", aboutRouter);
+    return app;
+  };
+
+  it("returns releases from a successful fetch", async () => {
+    const releases = [{ id: 1, name: "v1.0.0", body: "notes" }];
+    mockFetch.mockResolvedValueOnce({ ok: true, json: () => Promise.resolve(releases) });
+    const app = await makeApp();
+    const res = await app.fetch(new Request("http://localhost/about"));
+    expect(res.status).toBe(200);
+    const body = await res.json() as { releases: unknown[] };
+    expect(body.releases).toEqual(releases);
+  });
+
+  it("returns empty releases when fetch is not ok", async () => {
+    mockFetch.mockResolvedValueOnce({ ok: false });
+    const app = await makeApp();
+    const res = await app.fetch(new Request("http://localhost/about"));
+    expect(res.status).toBe(200);
+    const body = await res.json() as { releases: unknown[] };
+    expect(body.releases).toEqual([]);
+  });
+
+  it("returns empty releases when fetch throws", async () => {
+    mockFetch.mockRejectedValueOnce(new Error("Network error"));
+    const app = await makeApp();
+    const res = await app.fetch(new Request("http://localhost/about"));
+    expect(res.status).toBe(200);
+    const body = await res.json() as { releases: unknown[] };
+    expect(body.releases).toEqual([]);
+  });
+
+  it("returns cached releases on second call within TTL", async () => {
+    const releases = [{ id: 1, name: "v1.0.0", body: "notes" }];
+    mockFetch.mockResolvedValueOnce({ ok: true, json: () => Promise.resolve(releases) });
+    const app = await makeApp();
+    // First call populates cache
+    await app.fetch(new Request("http://localhost/about"));
+    // Second call should use cache, not call fetch again
+    const res = await app.fetch(new Request("http://localhost/about"));
+    expect(res.status).toBe(200);
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+  });
+
+  it("includes apiVersion in response", async () => {
+    mockFetch.mockResolvedValueOnce({ ok: true, json: () => Promise.resolve([]) });
+    const app = await makeApp();
+    const res = await app.fetch(new Request("http://localhost/about"));
+    expect(res.status).toBe(200);
+    const body = await res.json() as { apiVersion: string };
+    expect(typeof body.apiVersion).toBe("string");
+  });
+});