fix: update fetch_schemas_and_tables docstring to reflect dictionary return datatype

feat(engine): add metadata discovery and query history discovery functions

feat(engine): implement thread-safe Snowflake connection validation

chore(engine): initialize Snowflake client with security guardrails

feat(auth): implement secure account recovery workflow

fix: include logout endpoint missed in last commit due to unsaved files

feat(auth): implement core session lifecycle with enumeration defense

feat(security): implement MVP secret vault for connection credentials

feat(security): harden auth dependency against database outages

feat(security): implement JWT-based authentication and password hashing

fix(schemas): update helper functions to start with an underscore

feat(scans): add comprehensive scan config and response schemas

feat(schemas): add Connection schemas and secure Snowflake credentials with SecretStr and whitespace stripping

feat(schemas): implement project validation and response models

fix: include auth schemas missed in last commit due to unsaved files