Refactor enrollment validation error to break circular import

Data/Engine/services/enrollment/__init__.py

@@ -7,9 +7,9 @@ from .enrollment_service import (
     EnrollmentService,
     EnrollmentStatus,
     EnrollmentTokenBundle,
-    EnrollmentValidationError,
     PollingResult,
 )
+from Data.Engine.domain.device_enrollment import EnrollmentValidationError
 
 __all__ = [
     "EnrollmentRequestResult",

Data/Engine/services/enrollment/enrollment_service.py

@@ -23,10 +23,10 @@ from Data.Engine.domain.device_enrollment import (
     EnrollmentApproval,
     EnrollmentApprovalStatus,
     EnrollmentCode,
+    EnrollmentValidationError,
 )
 from Data.Engine.services.auth.device_auth_service import DeviceRecord
 from Data.Engine.services.auth.token_service import JWTIssuer
-from Data.Engine.services.enrollment.errors import EnrollmentValidationError
 from Data.Engine.services.enrollment.nonce_cache import NonceCache
 from Data.Engine.services.rate_limit import SlidingWindowRateLimiter
 

Data/Engine/services/enrollment/errors.py

@@ -1,26 +0,0 @@
-"""Error types shared across enrollment components."""
-
-from __future__ import annotations
-
-from dataclasses import dataclass
-from typing import Optional
-
-__all__ = ["EnrollmentValidationError"]
-
-
-@dataclass(frozen=True, slots=True)
-class EnrollmentValidationError(Exception):
-    """Raised when enrollment input fails validation."""
-
-    code: str
-    http_status: int = 400
-    retry_after: Optional[float] = None
-
-    def to_response(self) -> dict[str, object]:
-        payload: dict[str, object] = {"error": self.code}
-        if self.retry_after is not None:
-            payload["retry_after"] = self.retry_after
-        return payload
-
-    def __str__(self) -> str:  # pragma: no cover - debug helper
-        return f"{self.code} (status={self.http_status})"