refactor: extract static page routes into routes/pages.ts (TDD)

- Created src/routes/pages.ts with pagesRouter consolidating all page-serving
  routes: /, /docs, /impressum, /privacy, /terms, /examples, /status,
  /favicon.ico, /openapi.json, /api
- Reduced index.ts from 391 to 314 lines (20% reduction)
- Removed unused imports (createRequire, APP_VERSION, swaggerSpec) from index.ts
- 4 TDD tests verifying router exports and route definitions
- 622 tests passing, 0 tsc errors

src/__tests__/pages-router.test.ts

@@ -0,0 +1,77 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+// Mock sendFile to track calls
+const sendFileMock = vi.fn();
+const setHeaderMock = vi.fn().mockReturnThis();
+
+vi.mock("express", async () => {
+  const actual = await vi.importActual("express");
+  return actual;
+});
+
+describe("pages router", () => {
+  it("exports a pagesRouter express Router", async () => {
+    const { pagesRouter } = await import("../routes/pages.js");
+    expect(pagesRouter).toBeDefined();
+    expect(typeof pagesRouter).toBe("function"); // Express routers are functions
+  });
+
+  it("defines GET routes for all static pages", async () => {
+    const { pagesRouter } = await import("../routes/pages.js");
+    // Express Router stores routes in router.stack
+    const routes = (pagesRouter as any).stack
+      .filter((layer: any) => layer.route)
+      .map((layer: any) => ({
+        path: layer.route.path,
+        method: Object.keys(layer.route.methods)[0],
+      }));
+
+    const expectedPages = [
+      { path: "/", method: "get" },
+      { path: "/docs", method: "get" },
+      { path: "/impressum", method: "get" },
+      { path: "/privacy", method: "get" },
+      { path: "/terms", method: "get" },
+      { path: "/examples", method: "get" },
+      { path: "/status", method: "get" },
+      { path: "/favicon.ico", method: "get" },
+    ];
+
+    for (const expected of expectedPages) {
+      const found = routes.find(
+        (r: any) => r.path === expected.path && r.method === expected.method
+      );
+      expect(found, `Missing route: GET ${expected.path}`).toBeDefined();
+    }
+  });
+
+  it("defines GET /openapi.json route", async () => {
+    const { pagesRouter } = await import("../routes/pages.js");
+    const routes = (pagesRouter as any).stack
+      .filter((layer: any) => layer.route)
+      .map((layer: any) => ({
+        path: layer.route.path,
+        method: Object.keys(layer.route.methods)[0],
+      }));
+
+    const found = routes.find(
+      (r: any) => r.path === "/openapi.json" && r.method === "get"
+    );
+    expect(found, "Missing route: GET /openapi.json").toBeDefined();
+  });
+
+  it("defines GET /api route", async () => {
+    const { pagesRouter } = await import("../routes/pages.js");
+    const routes = (pagesRouter as any).stack
+      .filter((layer: any) => layer.route)
+      .map((layer: any) => ({
+        path: layer.route.path,
+        method: Object.keys(layer.route.methods)[0],
+      }));
+
+    const found = routes.find(
+      (r: any) => r.path === "/api" && r.method === "get"
+    );
+    expect(found, "Missing route: GET /api").toBeDefined();
+  });
+});