Add Postgres table adapter with TableRepositoryInterface.

Introduce PostgresAdapter for dict-based row CRUD via psycopg3, including config, lazy exports, unit/integration tests with testcontainers, and an example UserTableRepository.

Co-authored-by: Cursor <[email protected]>

tests/unit/conftest.py

@@ -5,12 +5,14 @@ from __future__ import annotations
 from unittest.mock import MagicMock
 
 from minio import Minio
+import psycopg
 import pytest
 import redis
 
 from python_repositories.adapters.minio_adapter import MinioAdapter
+from python_repositories.adapters.postgres_adapter import PostgresAdapter
 from python_repositories.adapters.redis_adapter import RedisAdapter
-from tests.conftest import TEST_MINIO_CONFIG, TEST_REDIS_CONFIG
+from tests.conftest import TEST_MINIO_CONFIG, TEST_POSTGRES_CONFIG, TEST_REDIS_CONFIG
 
 
 @pytest.fixture
@@ -25,3 +27,14 @@ def minio_adapter() -> MinioAdapter:
     """Provide a MinioAdapter with an injected mock client."""
     mock_client = MagicMock(spec=Minio)
     return MinioAdapter(config=TEST_MINIO_CONFIG, client=mock_client)
+
+
+@pytest.fixture
+def postgres_adapter() -> PostgresAdapter:
+    """Provide a PostgresAdapter with an injected mock client."""
+    mock_client = MagicMock(spec=psycopg.Connection)
+    mock_cursor = MagicMock()
+    mock_cursor.__enter__ = MagicMock(return_value=mock_cursor)
+    mock_cursor.__exit__ = MagicMock(return_value=False)
+    mock_client.cursor.return_value = mock_cursor
+    return PostgresAdapter(config=TEST_POSTGRES_CONFIG, client=mock_client)