fix(openapi): tighten _DISPATCH return type + cover helper edge cases

- _DISPATCH value type: tuple[Any, dict[str, Any] | None] (was Any, Any).
  Helpers always return one of (stream_obj, None) or (None, dict);
  tightened sig lets mypy flag wrong shapes when Task 3's route handler
  unpacks the result.
- Comment _run_completion's auto_generate_name + query mutations
  (legacy parity; non-obvious without grep-archaeology).
- Unit cover _unpack_blocking (mapping / tuple / non-mapping branches)
  + AppRunRequest.conversation_id field validator (strip-to-None,
  invalid-uuid raise, valid-uuid passthrough).

api/controllers/openapi/app_run.py

@@ -139,6 +139,7 @@ def _run_chat(app: App, caller: Any, payload: AppRunRequest, streaming: bool):
 
 def _run_completion(app: App, caller: Any, payload: AppRunRequest, streaming: bool):
     args = payload.model_dump(exclude_none=True)
+    # Completion mode disables auto-naming + tolerates absent query (legacy parity).
     args["auto_generate_name"] = False
     args.setdefault("query", "")
     try:
@@ -191,7 +192,7 @@ def _run_workflow(app: App, caller: Any, payload: AppRunRequest, streaming: bool
     return None, WorkflowRunResponse.model_validate(body).model_dump(mode="json")
 
 
-_DISPATCH: dict[AppMode, Callable[[App, Any, AppRunRequest, bool], tuple[Any, Any]]] = {
+_DISPATCH: dict[AppMode, Callable[[App, Any, AppRunRequest, bool], tuple[Any, dict[str, Any] | None]]] = {
     AppMode.CHAT: _run_chat,
     AppMode.AGENT_CHAT: _run_chat,
     AppMode.ADVANCED_CHAT: _run_chat,

api/tests/unit_tests/controllers/openapi/test_app_run_dispatch.py

@@ -1,11 +1,12 @@
 import pytest
-from werkzeug.exceptions import UnprocessableEntity
+from werkzeug.exceptions import InternalServerError, UnprocessableEntity
 
 from controllers.openapi.app_run import (
     _DISPATCH,
     AppRunRequest,
     _enforce_chat_constraint,
     _enforce_workflow_constraint,
+    _unpack_blocking,
 )
 from models.model import AppMode
 
@@ -23,3 +24,34 @@ def test_chat_constraint_requires_query():
 def test_workflow_constraint_rejects_query():
     with pytest.raises(UnprocessableEntity, match="query_not_supported_for_workflow"):
         _enforce_workflow_constraint(AppRunRequest(inputs={}, query="hi"))
+
+
+def test_unpack_blocking_passes_through_mapping():
+    assert _unpack_blocking({"a": 1}) == {"a": 1}
+
+
+def test_unpack_blocking_unwraps_tuple():
+    assert _unpack_blocking(({"a": 1}, 200)) == {"a": 1}
+
+
+def test_unpack_blocking_rejects_non_mapping():
+    with pytest.raises(InternalServerError):
+        _unpack_blocking("not a mapping")
+
+
+def test_app_run_request_strips_blank_conversation_id():
+    payload = AppRunRequest(inputs={}, conversation_id="   ")
+    assert payload.conversation_id is None
+
+
+def test_app_run_request_rejects_invalid_uuid_conversation_id():
+    from pydantic import ValidationError
+    with pytest.raises(ValidationError, match="conversation_id must be a valid UUID"):
+        AppRunRequest(inputs={}, conversation_id="not-a-uuid")
+
+
+def test_app_run_request_accepts_valid_uuid_conversation_id():
+    import uuid as _uuid
+    cid = str(_uuid.uuid4())
+    payload = AppRunRequest(inputs={}, conversation_id=cid)
+    assert payload.conversation_id == cid