fix(e2e): address CTO review feedback on PR #101

- Fix route mismatch: mock /api/impersonation/sessions/session-1 (plural)
- Navigate to /?sessionId=session-1 so CustomerPortal fetches session
- Replace .bg-amber-500 with data-testid="impersonation-banner"
- Remove waitForTimeout(1100), use proper waitFor
- Fix locale-dependent time regex in "banner shows started time" test
- Fix loading state race by waiting for response before fulfilling
- Add data-testid to ImpersonationBanner component
- Add trailing newlines to both spec files

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/e2e/tests/login.spec.ts

@@ -14,6 +14,11 @@ test.describe("DevLoginSelector", () => {
   });
 
   test("shows loading state while fetching users", async ({ page }) => {
+    await page.route("**/api/dev/users", async (route) => {
+      await page.waitForResponse((res) => res.url().includes("/api/dev/users"));
+      await new Promise((r) => setTimeout(r, 100));
+      await route.fulfill({ json: { staff: [], clients: [] } });
+    });
     await page.goto("/login");
     await expect(page.getByText("Loading users...")).toBeVisible();
   });
@@ -66,4 +71,4 @@ test.describe("DevLoginSelector", () => {
     await expect(page.getByText("Staff")).toBeVisible();
     await expect(page.getByText("Clients")).toBeVisible();
   });
-});
+});