feat: Support `column_policy` table option for CrateDB OBJECT type

[coderabbitai]

Overview

During the review of PR #27 (adding test_ddl_with_json_columns), the question was raised whether the dialect should also support and test CrateDB's column_policy table option (e.g. STRICT, DYNAMIC, IGNORED) in DDL generation.

Background

column_policy is a CrateDB table-level option that controls how columns are handled when inserting data that does not match the defined schema. It is not currently implemented in the dialect.

Currently implemented CrateDB-specific dialect options are:

• crate_number_of_shards
• crate_clustered_by
• crate_number_of_replicas
• crate_partitioned_by
• crate_index
• crate_columnstore

The ObjectType implementation does not currently handle any DDL-specific extras beyond what is defined in src/sqlalchemy_cratedb/type/object.py (lines 64–79).

Tasks

• Investigate whether column_policy should be added as a supported table option in the CrateDB dialect
• If implemented, add corresponding DDL compiler tests (e.g. column_policy = 'strict', column_policy = 'dynamic', column_policy = 'ignored')

References

• PR: Types: Emulate PostgreSQL's JSON(B) types using CrateDB's OBJECT #27
• Discussion comment: Types: Emulate PostgreSQL's JSON(B) types using CrateDB's OBJECT #27 (comment)