Initial commit: UTFCN — Use The (F***ing) Core Nodes

A ComfyUI companion that suggests core / available equivalents for custom
nodes and replaces them in a workflow.

- Backend (utfcn_core.py, __init__.py): read-only /utfcn/scan analysis that
  ranks equivalents in three tiers (curated → exact-signature → partial
  heuristic) from the live node registry.
- Frontend (web/utfcn.js): on-add mode (Off / Suggest / Force auto-replace),
  bulk "Replace with core / available…" command + Extensions menu with a
  preview-then-confirm dialog, and a right-click single-node replace. The swap
  engine only rewires losslessly.
- mappings.json: 7 hand-verified curated rules mined from installed packs
  (essentials, KJNodes, WAS); user_mappings.json for user overrides.
- Docs + branding: README, icon and social banner (SVG + PNG), GPL-3.0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

__init__.py

@@ -0,0 +1,62 @@
+"""
+UTFCN — Use The F***ing Core Nodes.
+
+A ComfyUI companion that nudges workflows back toward core nodes:
+
+  1. Suggests a core (or otherwise-available) equivalent when you add a custom
+     node that re-implements something ComfyUI already ships.
+  2. Adds a "Replace custom nodes with core / available…" command + menu entry
+     that scans the open graph and, after a preview, swaps in equivalents.
+  3. Adds a right-click "Replace with core / available" item on individual nodes.
+
+All of that is frontend behaviour (see web/utfcn.js).  This backend only serves
+the *analysis*: it has the live node registry, so it computes — accurately, from
+real INPUT_TYPES / RETURN_TYPES — which custom nodes have safe equivalents.
+
+  GET /utfcn/scan[?refresh=1]   -> { sources, candidates, stats }
+
+Curated overrides live in mappings.json (shipped) and user_mappings.json (yours).
+"""
+
+import os
+
+from aiohttp import web
+from server import PromptServer
+
+from . import utfcn_core
+
+VERSION = "1.0.0"
+_DIR = os.path.dirname(os.path.realpath(__file__))
+
+# The scan walks the whole registry, so we cache it and only rebuild on demand.
+_INDEX_CACHE = None
+
+
+def _get_index(refresh=False):
+    global _INDEX_CACHE
+    if refresh or _INDEX_CACHE is None:
+        rules = utfcn_core.load_rules(_DIR)
+        _INDEX_CACHE = utfcn_core.build_index(rules)
+    return _INDEX_CACHE
+
+
+routes = PromptServer.instance.routes
+
+
+@routes.get("/utfcn/scan")
+async def utfcn_scan(request):
+    refresh = request.query.get("refresh") in ("1", "true", "yes")
+    try:
+        return web.json_response(_get_index(refresh))
+    except Exception as e:
+        # never let a scan failure break the editor — the frontend degrades gracefully
+        print(f"[UTFCN] scan failed: {e}")
+        return web.json_response({"sources": {}, "candidates": {}, "stats": {}, "error": str(e)}, status=500)
+
+
+WEB_DIRECTORY = "./web"
+NODE_CLASS_MAPPINGS = {}
+NODE_DISPLAY_NAME_MAPPINGS = {}
+__all__ = ["NODE_CLASS_MAPPINGS", "NODE_DISPLAY_NAME_MAPPINGS", "WEB_DIRECTORY"]
+
+print(f"[UTFCN] loaded (v{VERSION}) — Use The F***ing Core Nodes")