Introduce aether-data-schema and driver-specific schema generation for Postgres, MySQL, and SQLite.
Split data backends, lifecycle, repositories, and gateway runtime integration across database drivers.
Verified with cargo fmt --all --check, cargo clippy --workspace --all-targets -- -D warnings, and cargo test --workspace.
Extract request_auth_channel as a distinct routing dimension to distinguish
between api_key and bearer_like authentication methods. This improves routing
clarity by decoupling authentication mechanism from route classification.
fawney19