# Data Layer

`internal/data` is the persistence composition root. It owns the shared
database/runtime container (`Data`), database clients, configuration storage,
and the Wire `ProviderSet`. Business repositories live in submodules so a new
feature can be found by its domain instead of by scanning one large package.

## Modules

- `internal/data/system` contains the built-in administration domain: users,
  authorities, APIs, permissions, menus, organization, dictionaries,
  parameters, tokens, security, audit/logging, media, announcements, tasks,
  versions, exports, bootstrap seeding, and system migrations.
- `internal/data/payment` contains payment configuration and payment-order
  persistence. Provider SDK implementations are separate in
  `internal/integration/payment`.
- `internal/data/migration` contains the version-table runner used by the
  root migration coordinator.

The root package intentionally keeps only cross-cutting infrastructure:
database lifecycle/reloads, runtime configuration persistence, data-scope
auditing, integration configuration storage, and migration orchestration.
Repositories depend on narrow module seams (`system.Provider` and
`payment.Provider`) rather than importing the root implementation details.

Non-database adapters remain under `internal/integration` (storage, email,
payment SDKs, and cache), while reusable GORM and pagination helpers live in
`pkg/gormkit` and `pkg/pagination`.