test(api): achieve 100% coverage across all routes, middleware, and services

- Add full test suite for frontend.ts (POST /log and POST /error)
- Add error-path tests to all route handlers to cover catch blocks
  triggered by Prisma rejections
- Add non-Error throw tests to cover the `new Error(String(error))`
  ternary false branch in middleware, services, and route catch handlers
- Suppress unreachable outer catch in about.ts with v8 ignore (fetchReleases
  swallows all errors internally, making the outer catch genuinely dead code)

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

@@ -293,4 +293,16 @@ describe("boss route", () => {
     const body = await res.json() as { won: boolean };
     expect(body.won).toBe(true);
   });
+
+  it("returns 500 when the database throws", async () => {
+    vi.mocked(prisma.gameState.findUnique).mockRejectedValueOnce(new Error("DB error"));
+    const res = await challenge({ bossId: "test_boss" });
+    expect(res.status).toBe(500);
+  });
+
+  it("returns 500 when the database throws a non-Error value", async () => {
+    vi.mocked(prisma.gameState.findUnique).mockRejectedValueOnce("raw string error");
+    const res = await challenge({ bossId: "test_boss" });
+    expect(res.status).toBe(500);
+  });
 });