feat: added-trait-model-type (#186)

Author: Zaimwa9

flagsmith/api/types.py

@@ -1,5 +1,6 @@
 import typing
 
+from flag_engine.engine import ContextValue
 from flag_engine.segments.types import ConditionOperator, RuleType
 from typing_extensions import NotRequired
 
@@ -67,3 +68,9 @@ class EnvironmentModel(typing.TypedDict):
     identity_overrides: list[IdentityModel]
     name: str
     project: ProjectModel
+
+
+class TraitModel(typing.TypedDict):
+    trait_key: str
+    trait_value: ContextValue
+    transient: NotRequired[bool]