feat: make fully standalone — remove local LoRA Manager dependency

Proxy JS widget files from the remote instance via /extensions/ComfyUI-Lora-Manager/
prefix, and handle send_sync routes locally instead of falling through to the
original package. This eliminates the requirement to install ComfyUI-Lora-Manager
alongside.

- Add /extensions/ComfyUI-Lora-Manager/ to proxy prefixes
- Replace _SEND_SYNC_SKIP_ROUTES with local handler functions that fetch
  data from remote and broadcast events via PromptServer.send_sync()
- Add lm_remote_bootstrap.js to load Vue widget bundle from remote
- Update docstrings and README to reflect standalone operation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/comfyui/lm_remote_bootstrap.js

@@ -0,0 +1,25 @@
+/**
+ * Bootstrap loader for LoRA Manager Vue widget bundle.
+ *
+ * When the original ComfyUI-Lora-Manager package is NOT installed locally,
+ * the Vue widget types (AUTOCOMPLETE_TEXT_LORAS, LORAS, LORA_POOL_CONFIG,
+ * RANDOMIZER_CONFIG, CYCLER_CONFIG) would never be registered and nodes
+ * wouldn't render.
+ *
+ * This script loads the Vue widget bundle from the remote instance via the
+ * proxy at /extensions/ComfyUI-Lora-Manager/vue-widgets/.  If the original
+ * package IS installed, the bundle is already loaded and we skip the import.
+ */
+import { app } from "../../scripts/app.js";
+
+const alreadyLoaded = app.extensions?.some(
+    ext => ext.name === "LoraManager.VueWidgets"
+);
+
+if (!alreadyLoaded) {
+    try {
+        await import("/extensions/ComfyUI-Lora-Manager/vue-widgets/lora-manager-widgets.js");
+    } catch (err) {
+        console.warn("[LM-Remote] Failed to load Vue widget bundle:", err);
+    }
+}