fix: address Copilot review - empty name handling and type annotation

- _sanitize_author_name returns None for empty string (avoids invalid
  OpenAI name field that doesn't match ^[^\s<|\\/>]+$ regex)
- Fix create_agents return type: dict[str, Agent] not list[Agent]
- Update test assertion to match new empty-string behavior

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Prachig-Microsoft

src/processor/src/libs/agent_framework/azure_openai_response_retry.py

@@ -284,8 +284,10 @@ def _sanitize_author_name(name: Any) -> Any:
     empty (e.g. name was all whitespace), returns ``None`` so the field can be
     dropped entirely.
     """
-    if not isinstance(name, str) or not name:
+    if not isinstance(name, str):
         return name
+    if not name:
+        return None
     if not _OPENAI_NAME_INVALID_CHARS.search(name):
         return name
     sanitized = _OPENAI_NAME_INVALID_CHARS.sub("_", name).strip("_")

src/processor/src/libs/base/orchestrator_base.py

@@ -145,7 +145,7 @@ async def prepare_agent_infos(self) -> list[AgentInfo]:
 
     async def create_agents(
         self, agent_infos: list[AgentInfo], process_id: str
-    ) -> list[Agent]:
+    ) -> dict[str, Agent]:
         agents = dict[str, Agent]()
         agent_client = await self.get_client(thread_id=process_id)
 

src/processor/src/tests/unit/libs/agent_framework/test_azure_openai_response_retry_utils.py

@@ -111,7 +111,7 @@ def test_sanitize_author_name_replaces_whitespace_and_specials() -> None:
 
 def test_sanitize_author_name_handles_edge_cases() -> None:
     assert _sanitize_author_name(None) is None
-    assert _sanitize_author_name("") == ""
+    assert _sanitize_author_name("") is None
     assert _sanitize_author_name(123) == 123
     # All-invalid input collapses to empty -> None (so callers drop the field).
     assert _sanitize_author_name("   ") is None