feat: Implement SQLAlchemy enum helper and normalize enum values in database initialization

models/enums.py

@@ -1,6 +1,21 @@
 from __future__ import annotations
 
 from enum import Enum
+from typing import Type
+
+from sqlalchemy import Enum as SQLEnum
+
+
+def sql_enum(enum_cls: Type[Enum], *, name: str) -> SQLEnum:
+    """Build a SQLAlchemy Enum that maps using the enum member values."""
+
+    return SQLEnum(
+        enum_cls,
+        name=name,
+        create_type=False,
+        validate_strings=True,
+        values_callable=lambda enum_cls: [member.value for member in enum_cls],
+    )
 
 
 class MiningOperationType(str, Enum):