`tensor_to_png_bytes` imported torch unconditionally inside its try block,
so every run without torch (standalone, CI) hit ModuleNotFoundError, logged
it as an image-processing error and returned None. That silently disabled
workflow previews on standalone installs and failed two backend tests:
`test_tensor_to_png_bytes_*` and
`test_resolve_workflow_preview_requires_matching_prompt`.
Detect torch tensors behind an optional import instead; numpy arrays keep
converting as before when torch is absent.
- Replace the multi-root folder_paths.workflows workflow library with a
scalar workflow_path setting (Settings > Library); remove the
extra_folder_paths.workflows path and the standalone Model Paths editor.
- Migrate pre-release settings.json files that still keep
folder_paths.workflows / extra_folder_paths.workflows on startup, so an
upgrade keeps the configured folder instead of silently losing it.
- Add "Create LM-managed workflow" to the ComfyUI Graph menu and the File
menu/command palette: it writes the serialized graph into the configured
folder, stamps extra.lm_source and registers the entry in the scanner
cache without forcing a rescan.
- Attach the decode image of the client's last executed prompt as the
workflow preview. The prompt id is sent with the create request and the
backend only honors it while it is still the registry's current prompt,
so a tab never borrows another tab's output; otherwise the card keeps the
placeholder preview.
- Detect library entries deleted/renamed while a graph still carries the
marker: a link-status endpoint clears the stale extra.lm_source (on graph
load, menu open and before create/update), and the write-back route
returns 404 instead of recreating the document.
- Collapse the workflows.noPaths standalone/ComfyUI split into a single
description/hint; the folder is edited in Settings > Library in both
modes, so the manual settings.json guidance and the standalone
open-settings-folder fallback are gone.
- Add the preview tensor conversion as a shared utility (reused by the
recipe widget save path) and cover create, preview gating, link status,
migration and menu injection with tests.
Will Miao