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]>

python_repositories/adapters/__init__.py

@@ -12,6 +12,7 @@ from typing import TYPE_CHECKING
 # Adapters are imported only for static type checkers; runtime loading is deferred below.
 if TYPE_CHECKING:
     from .minio_adapter import MinioAdapter
+    from .postgres_adapter import PostgresAdapter
     from .redis_adapter import RedisAdapter
 
 # Map public adapter names to their defining module and class.
@@ -20,11 +21,13 @@ if TYPE_CHECKING:
 _LAZY_EXPORTS = {
     "RedisAdapter": (".redis_adapter", "RedisAdapter"),
     "MinioAdapter": (".minio_adapter", "MinioAdapter"),
+    "PostgresAdapter": (".postgres_adapter", "PostgresAdapter"),
 }
 
 __all__ = [
     "RedisAdapter",
     "MinioAdapter",
+    "PostgresAdapter",
 ]