refactor(workspace): enforce layered crate boundaries

crates/aether-data/runtime/src/lib.rs

@@ -0,0 +1,38 @@
+//! Runtime data access for Aether.
+//!
+//! This crate is the runtime composition facade. It selects concrete SQL
+//! adapters, owns in-memory repositories and maintenance/backfill/export
+//! workflows, and exposes application-facing backend handles. Shared repository
+//! contracts live in `aether-data-contracts`; request-path SQL and executable
+//! migrations live in the driver adapter crates.
+//!
+//! See `crates/aether-data/runtime/README.md` for the layer map and SQL driver policy.
+
+pub mod backend;
+mod config;
+mod database;
+pub mod driver;
+mod error;
+pub mod lifecycle;
+pub mod maintenance;
+pub mod repository;
+
+#[cfg(feature = "mysql")]
+pub use backend::MysqlBackend;
+#[cfg(feature = "postgres")]
+pub use backend::PostgresBackend;
+#[cfg(feature = "sqlite")]
+pub use backend::SqliteBackend;
+pub use backend::{
+    DataBackends, DataLeaseBackends, DataReadRepositories, DataTransactionBackends,
+    DataWriteRepositories,
+};
+pub use config::DataLayerConfig;
+pub use database::{DatabaseDriver, SqlDatabaseConfig, SqlPoolConfig, DEFAULT_SQLITE_DATABASE_URL};
+pub use error::DataLayerError;
+pub use maintenance::{
+    DatabaseMaintenanceSummary, DatabasePoolSummary, DatabasePostgresActivityGroup,
+    DatabasePostgresObservabilitySnapshot, StatsDailyAggregationInput,
+    StatsDailyAggregationSummary, StatsHourlyAggregationInput, StatsHourlyAggregationSummary,
+    WalletDailyUsageAggregationInput, WalletDailyUsageAggregationResult,
+};