Stratara.Identity.Core 3.1.0

• net10.0

  • Stratara.Shared (>= 3.1.0)

**Breaking release.** The `IKeyStore` and `ISecureBlobEncryptor` contracts changed shape, a new
dependency-light `Stratara.Security` package now owns the production key store and envelope
encryption, and a new vendor-neutral `Stratara.Validation` package adds request validation as a
`Stratara.Mediator` pipeline behavior. Consumers must recompile and adapt call sites; data
encrypted under the previous HKDF-style key model is **not** binary-compatible and needs a
re-encrypt pass on its own schedule.

### Added

- **`Stratara.Validation` — vendor-neutral request validation.** A new package providing a
 mediator pipeline behavior that runs `IValidator<T>` implementations before the handler and
 throws an aggregated `StrataraValidationException` on failure. Register with
 `AddStrataraValidation()` (outermost behavior) and `AddValidatorsFromAssemblyContaining<T>()`.
 Only `ValidationSeverity.Error` blocks the request; `Warning`/`Info` failures pass through and
 are logged. The package has no FluentValidation dependency — the contract is intentionally
 FluentValidation-shape-compatible so an optional adapter can be added later.
- **Validation contracts in `Stratara.Abstractions`** (namespace `Stratara.Abstractions.Validation`):
 `IValidator<T>`, `ValidationResult`, `ValidationFailure`, `ValidationSeverity`, and
 `StrataraValidationException`. Declaring the exception in `Stratara.Abstractions` lets a
 consumer's global exception handler map validation failures to its own error model (e.g.
 RFC-7807 ProblemDetails) without referencing the behavior package.
- **`Stratara.Security` — production key store + envelope encryption (dependency-light).** Adds
 `EnvelopeFileKeyStore`, a file-backed `IKeyStore` storing **KEK-wrapped, versioned per-scope
 data-encryption keys** (rotation, single-version revoke, and whole-scope crypto-shred), plus a
 `FileMasterKeyProvider` (`IMasterKeyProvider`, the KEK custody seam), an AES-GCM
 `ISecureBlobEncryptor`, and the Development-only `DummyKeyStore`. Register with
 `AddStrataraFileKeyStore(configuration)`. The package references only `Stratara.Abstractions` +
 BCL crypto + `Microsoft.Extensions.*` abstractions — no EF Core, RabbitMQ, Redis, or cloud SDKs —
 so lean consumers can encrypt without pulling in `Stratara.Infrastructure`.
- **New security contracts in `Stratara.Abstractions.Security`:** `KeyScope`, `KeyMaterial`, and
 `IMasterKeyProvider`.

### Changed

- **BREAKING — `IKeyStore`.** Replaced `EnsureKeyAsync(level, Guid? tenantId, Guid? userId)` with
 `GetOrCreateCurrentKeyAsync(KeyScope)` returning `KeyMaterial` (key id + bytes in one call), and
 added `RotateAsync(KeyScope)` and `EraseScopeAsync(KeyScope)`. `RevokeAsync(string keyId)` now
 performs a real crypto-shred (the production store no longer treats it as a no-op). Scope
 identifiers are `string?` (carrying both slugs and `Guid.ToString()` values) rather than `Guid?`.
- **BREAKING — `ISecureBlobEncryptor`.** `EncryptAsync`/`DecryptAsync` now take a `KeyScope` and a
 `purpose` instead of a bare `Guid tenantId`. The encrypted stream gains a leading version byte
 (v2) and a `purpose` field; legacy streams without the version byte remain readable (configurable
 via `Stratara.Security` options).
- The AES-GCM encryption factory, blob encryptor, and dev key store moved out of
 `Stratara.Infrastructure` into `Stratara.Security`; `AddSecurity()` now delegates to it. The
 field/JSON `[EncryptData]` path (`ISecureJsonSerializer`) stays in `Stratara.Infrastructure`.

This brings the lockstep family to **22 packable packages**.