Problem

LearningSession model (deeptutor/models/learning_session.py) has no metadata field. When agents (Tutor, QA) try to read knowledge point info via session.metadata.get("knowledge_point_title"), they get empty/default values because the attribute doesn't exist.

Steps to Reproduce

1. Start a learning session with POST /sessions/start
2. Send a message via POST /sessions/{id}/message
3. Agent receives empty knowledge point title and description

Expected

Agents should have access to the knowledge point context (title, description) to provide meaningful responses.

Fix

Add a metadata field to LearningSession:

class LearningSession(BaseModel):
    ...
    metadata: dict[str, Any] = Field(default_factory=dict)
    ...

And store knowledge point info when starting a session:

session.metadata["knowledge_point_title"] = request.knowledge_point_title
session.metadata["knowledge_point_description"] = request.knowledge_point_description

Environment

• Python 3.14, Windows 11, latest main branch