Consolidate subscription usage policy enforcement, privacy-safe persistence, and gateway security hardening into one reviewable change.
Includes bounded HTTP and execution envelopes, header and protocol guards, DNS and relay validation, authentication and secret projection hardening, secure backup/install paths, and regression coverage.
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.