Adding Dashboard Routes

Use the existing dashboard layers:

Content	Location
Router	dojoagents/dashboard/routers/
Schemas	dojoagents/dashboard/schemas/
Business logic	dojoagents/dashboard/services/
Dependencies	dojoagents/dashboard/deps.py
App include	dojoagents/dashboard/server.py

Expected HTTP failures should use fastapi.HTTPException or the existing JSONResponse(status_code=..., content={"error": ...}) pattern.