Refactor application ports to 12000 for backend and 12001 for frontend; update documentation and configuration files accordingly

Co-authored-by: Copilot <copilot@github.com>

backend/app/main.py

@@ -30,7 +30,7 @@ app = FastAPI(
 
 app.add_middleware(
     CORSMiddleware,
-    allow_origins=[os.getenv("CORS_ORIGINS", "http://localhost:5000")],
+    allow_origins=[os.getenv("CORS_ORIGINS", "http://localhost:12001")],
     allow_credentials=True,
     allow_methods=["*"],
     allow_headers=["*"],