LCORE-2492: Use optiona data types consistently

Author: tisnik

src/models/common/agents/turn_accumulator.py

@@ -1,7 +1,7 @@
 """Mutable per-turn state for agent response processing."""
 
 from dataclasses import dataclass, field
-from typing import Final
+from typing import Final, Optional
 
 from pydantic_ai import AgentRunResult
 
@@ -29,7 +29,7 @@ class AgentTurnAccumulator:  # pylint: disable=too-many-instance-attributes
     vector_store_ids: Final[list[str]]
     rag_id_mapping: Final[dict[str, str]]
     turn_summary: TurnSummary
-    run_result: AgentRunResult[str] | None = None
+    run_result: Optional[AgentRunResult[str]] = None
     chunk_id: int = 0
     text_parts: list[str] = field(default_factory=list)
     tool_round: int = 1

src/pydantic_ai_lightspeed/llamastack/_provider.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations as _annotations
 
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Optional
 
 import httpx
 from openai import AsyncOpenAI
@@ -44,17 +44,17 @@ def client(self) -> AsyncOpenAI:
         return self._client
 
     @staticmethod
-    def model_profile(model_name: str) -> ModelProfile | None:
+    def model_profile(model_name: str) -> Optional[ModelProfile]:
         """Return the model profile for the named model, if available."""
         return openai_model_profile(model_name)
 
     def __init__(
         self,
         *,
-        base_url: str | None = None,
-        api_key: str | None = None,
-        library_client: AsyncLlamaStackAsLibraryClient | None = None,
-        http_client: httpx.AsyncClient | None = None,
+        base_url: Optional[str] = None,
+        api_key: Optional[str] = None,
+        library_client: Optional[AsyncLlamaStackAsLibraryClient] = None,
+        http_client: Optional[httpx.AsyncClient] = None,
     ) -> None:
         """Create a new Llama Stack provider.