feat: add ClassifiedAdId value object and use it in ClassifiedAd

tests/test_classified_ad_id.py

@@ -0,0 +1,25 @@
+from uuid import UUID, uuid4
+
+from domain.marketplace.classified_ad_id import ClassifiedAdId
+
+
+def test_classified_ad_id_creation():
+    ad_id = ClassifiedAdId(value=uuid4())
+    assert isinstance(ad_id.value, UUID)
+
+
+def test_classified_ad_id_is_immutable():
+    ad_id = ClassifiedAdId(value=uuid4())
+
+    try:
+        ad_id.value = uuid4()  # type: ignore
+        assert False, "Should have raised FrozenInstanceError"
+    except AttributeError:
+        pass
+
+
+def test_classified_ad_id_equality():
+    uid = uuid4()
+    ad_id1 = ClassifiedAdId(value=uid)
+    ad_id2 = ClassifiedAdId(value=uid)
+    assert ad_id1 == ad_id2