Update admin theme/layout and refresh README details.

Align the project baseline with the latest admin interface styling and layout structure while documenting setup and usage updates in README.

apps/api/tests/modules/auth/test_rate_limit.py

@@ -0,0 +1,22 @@
+from uuid import uuid4
+
+
+def test_login_rate_limit(client, monkeypatch):
+    from app.core.config import settings
+
+    monkeypatch.setattr(settings, "enable_rate_limit", True)
+
+    email = f"missing-{uuid4().hex}@example.com"
+    for _ in range(5):
+        response = client.post(
+            "/api/v1/auth/login",
+            json={"email": email, "password": "Valid123"},
+        )
+        assert response.status_code == 401
+
+    blocked = client.post(
+        "/api/v1/auth/login",
+        json={"email": email, "password": "Valid123"},
+    )
+    assert blocked.status_code == 429
+    assert blocked.json()["detail"] == "RATE_LIMIT_EXCEEDED"