fix: handle PartEndEvent from pydantic-ai 1.9.0+ (#1240)

PartEndEvent was added in pydantic-ai v1.9.0 (PR #2923) as part of the
Vercel AI Data Stream Protocol support. This event signals when a part
is complete during streaming.

Changes:
- Import PartEndEvent from pydantic_ai.messages
- Add handler in _process_pydantic_event to acknowledge PartEndEvent
  without emitting a Marvin event (completion is handled via other
  events like FunctionToolCallEvent and FinalResultEvent)
- Update pydantic-ai dependency from >=0.7.2 to >=1.9.0 to ensure
  PartEndEvent is available

This fixes the "Unknown event type: PartEndEvent" warnings that started
appearing after pydantic-ai was updated.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: zzstoatzz

pyproject.toml

@@ -10,7 +10,7 @@ dependencies = [
     "alembic>=1.12.0",
     "jinja2>=3.1.4",
     "partial-json-parser>=0.2.1.1.post5",
-    "pydantic-ai>=0.7.2",
+    "pydantic-ai>=1.9.0",
     "pydantic-settings>=2.6.1",
     "pydantic[email]>=2.10.6",
     "rich>=13.9.4",

src/marvin/engine/streaming.py

@@ -10,6 +10,7 @@
     FunctionToolResultEvent,
     ModelResponsePart,
     PartDeltaEvent,
+    PartEndEvent,
     PartStartEvent,
     RetryPromptPart,
     TextPartDelta,
@@ -236,6 +237,13 @@ def _get_snapshot(index: int) -> ModelResponsePart | None:
                 tool_call_id=snapshot.tool_call_id if snapshot else None,
                 tool=tools_map.get(event.part.tool_name),
             )
+    # Handle Part End Events
+    elif isinstance(event, PartEndEvent):
+        # Part end events signal that a part is complete. We don't need to
+        # emit a Marvin event for this since we handle completion via other
+        # events (FunctionToolCallEvent, FinalResultEvent, etc.)
+        return None
+
     # Handle Part Delta Events
     elif isinstance(event, PartDeltaEvent):
         # Process a delta update to an existing part