fix: add pgdata volume for persistence + fix seed path

backend/seed.py

@@ -1,7 +1,6 @@
 """Seed demo data for ServeSync"""
 import sys
 import os
-sys.path.insert(0, '/app')
 
 from sqlalchemy.orm import Session
 from app.database import engine, SessionLocal

backend/start.sh

@@ -15,7 +15,7 @@ except Exception as e:
 done
 
 echo "Running seed..."
-python seed.py || echo "Seed already ran or error (continuing)"
+cd /app && python seed.py 2>&1 && echo "Seed complete" || echo "Seed failed or already ran (continuing)"
 
 echo "Starting server..."
 exec uvicorn app.main:app --host 0.0.0.0 --port 8000