db2pq 0.0.4

• Added first-class WRDS credential helpers: wrds_get_username(), wrds_conninfo(), and wrds_check_credentials().
• Added Parquet-first public helpers for schema/table listing and WRDS SQL exports: db_schema_tables(), wrds_get_tables(), db_schema_to_pq(), and wrds_sql_to_pq().
• Added pq_data_dir() to inspect or resolve the default Parquet repository directory.
• Added rename support to db_to_pq() and wrds_update_pq().
• Added pkgdown site configuration and workflow-oriented vignettes.
• Added ADBC diagnostics and clearer SSL-related error messages for the optional ADBC PostgreSQL path.