frostlake - 'DBI' Backend for the 'Frostlake' Database Engine

A 'DBI'-compliant driver for 'Frostlake', a SQL engine emulating core 'Snowflake' features. Speaks the engine's HTTP protocol against a running 'DatabaseHttpServer': one POST per statement with a session id the server issues on first contact, so session state (current database/schema, transactions) persists across statements. Query results arrive as data frames with Snowflake types mapped to R types.