[backport] Cherry-pick manager flag refactor to core/1.27#5646

christian-byrne merged 1 commit intocore/1.27Comfy-Org/ComfyUI_frontend:core/1.27from

hotfix/1.27.6-20250918Comfy-Org/ComfyUI_frontend:hotfix/1.27.6-20250918Copy head branch name to clipboard