Add stack Update, ComfyUI model manager, and slim ComfyUI stack.

Server UI gains Update on stack cards, ComfyUI Models tab with workflow
scan and downloads, and centralized comfyui_config. Model catalog and
download scripts move from stacks/comfyui to server-ui so ComfyUI stays a
minimal Docker wrapper for easier image updates.

stacks/server-ui/comfyui_manager_catalog.py

@@ -0,0 +1,65 @@
+"""Index ComfyUI-Manager model-list.json for filename → download URL lookup."""
+
+from __future__ import annotations
+
+import json
+import logging
+from pathlib import Path
+from typing import Any
+
+from comfyui_config import host_custom_nodes_dir
+
+log = logging.getLogger(__name__)
+
+MANAGER_REL_PATHS = (
+    "custom_nodes/ComfyUI-Manager/model-list.json",
+    "custom_nodes/ComfyUI-Manager/node_db/new/model-list.json",
+)
+
+
+def _manager_list_paths(data_root: Path) -> list[Path]:
+    base = host_custom_nodes_dir(data_root).parent
+    paths: list[Path] = []
+    for rel in MANAGER_REL_PATHS:
+        path = base / rel
+        if path.is_file():
+            paths.append(path)
+    return paths
+
+
+def _score_entry(entry: dict[str, Any]) -> tuple[int, int]:
+    """Prefer entries with URL and shorter save_path."""
+    has_url = 0 if entry.get("url") else 1
+    save_path = str(entry.get("save_path") or "")
+    return (has_url, len(save_path))
+
+
+def load_manager_index(data_root: Path) -> dict[str, dict[str, Any]]:
+    """Build filename → best matching ComfyUI-Manager entry."""
+    index: dict[str, dict[str, Any]] = {}
+    for list_path in _manager_list_paths(data_root):
+        try:
+            with list_path.open(encoding="utf-8") as fh:
+                data = json.load(fh)
+        except (OSError, json.JSONDecodeError) as exc:
+            log.warning("Failed to read ComfyUI-Manager list %s: %s", list_path, exc)
+            continue
+        models = data.get("models") if isinstance(data, dict) else None
+        if not isinstance(models, list):
+            continue
+        for entry in models:
+            if not isinstance(entry, dict):
+                continue
+            filename = entry.get("filename")
+            if not isinstance(filename, str) or not filename:
+                continue
+            existing = index.get(filename)
+            if existing is None or _score_entry(entry) < _score_entry(existing):
+                index[filename] = entry
+    return index
+
+
+def lookup_manager_entry(
+    data_root: Path, filename: str
+) -> dict[str, Any] | None:
+    return load_manager_index(data_root).get(filename)