feat(catalog): add description field to column models

Add optional description field to SqlColumn and CatalogDeclarativeColumn
to support database column comments. This enables passing column
descriptions from scanModel API to LDM generation.

risk: low
jira: DX-312

Author: tychtjan

packages/gooddata-sdk/src/gooddata_sdk/catalog/data_source/action_model/sql_column.py

@@ -11,6 +11,7 @@
 class SqlColumn(Base):
     data_type: str
     name: str
+    description: str | None = None
 
     @staticmethod
     def client_class() -> type[ApiSqlColumn]:

packages/gooddata-sdk/src/gooddata_sdk/catalog/data_source/declarative_model/physical_model/column.py

@@ -11,6 +11,7 @@
 class CatalogDeclarativeColumn(Base):
     name: str
     data_type: str
+    description: str | None = None
     is_primary_key: bool | None = None
     referenced_table_id: str | None = None
     referenced_table_column: str | None = None