fix(preview)+refactor(js): native in-node preview, de-vendor Fuse.js (main)

Port from feat:
- Remove js/c2c_live_preview.js. The custom overlay drew on the node, over-
  lapping ComfyUI's own native in-node preview (latent_preview.py) — the
  "popup that shows nothing". Display is now 100% native. The backend guard
  (_c2c_preview_guard.py) is kept BUT clarified as backend-only: it just keeps
  ComfyUI's own previewer running (no draw, no node touch), so native preview
  survives --preview-method none / bad core updates without overlapping core.
- De-vendor Fuse.js: js/vendor/fuse.min.mjs -> js/_fuse.mjs (part of the code
  tree, Apache-2.0 header intact), import updated, empty js/vendor/ removed.

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

Author: Code2Collapse

js/vendor/fuse.min.mjs js/_fuse.mjsjs/vendor/fuse.min.mjs renamed to js/_fuse.mjs

@@ -26,7 +26,7 @@
 import { app } from "../../scripts/app.js";
 import { reportFailure as __c2cReport } from "./_c2c_report.js";
 import { C } from './_c2c_theme.js';
-import Fuse from "./vendor/fuse.min.mjs";
+import Fuse from "./_fuse.mjs";
 import { capabilityFor } from "./c2c_node_taxonomy.js";
 
 const STYLE_ID = "c2c-workflow-find-style";

js/c2c_live_preview.js

@@ -17,8 +17,13 @@
     nodes should work").
   - Opt out with env var C2C_NO_FORCE_PREVIEW=1.
 
-This pairs with js/c2c_live_preview.js, which renders a resilient HUD from the
-`b_preview` / `progress` websocket events the server now emits.
+No frontend overlap: this is BACKEND ONLY. It does not draw anything and does
+not touch any node — it merely ensures ComfyUI's OWN previewer runs, so the
+NATIVE in-node latent preview (latent_preview.py) displays during sampling.
+There is deliberately no custom JS preview; ComfyUI core renders the preview
+on the node. The get_previewer wrapper is purely additive (returns core's own
+result untouched whenever core produces one) and fully guarded, so a bad
+ComfyUI update can never break or be damaged by it.
 """
 from __future__ import annotations