Refine knowledge brain workflow

Align the brain prompts, graph view, and startup defaults with the
latest phase 1 flow so local runs and navigation stay consistent.

backend/Dockerfile

@@ -18,4 +18,4 @@ RUN mkdir -p /data/jarvis/data /data/jarvis/chroma /data/jarvis/uploads
 
 EXPOSE 9527
 
-CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "9527"]
+CMD ["sh", "-c", "uvicorn app.main:app --host ${HOST:-0.0.0.0} --port ${PORT:-9527}"]