feat: disabled mode (TENACIOUSLOAD_DISABLED=1) — no-op but keep the loading bar

A one-flag kill-switch: when set, the pack installs no middleware, registers no
refresh routes, computes no fingerprint and exposes no graph node — ComfyUI runs
exactly as if it weren't installed. Only the read-only /tenaciousload/status
route stays so the loading-screen overlay still shows (a generic 'Loading node
definitions…' bar, since there's no build to track). The refresh menu buttons
hide themselves when status reports enabled:false.

Useful for A/B testing or as a safety kill-switch. Requires a restart (the
middleware is installed at startup). Unit-tested both modes.

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

web/loading-status.js

@@ -71,12 +71,19 @@ async function tick() {
             : `first build / refresh · ${fmt(st.elapsed || 0)}`;
         bar.classList.add("indet");
         bar.style.width = "35%";
-    } else {
+    } else if (st && st.cached) {
+        // known fast path: serving the cached object_info
         msg.textContent = "Loading node definitions…";
-        sub.textContent = st && st.cached ? `from cache · ${mb(st.gz_bytes || st.cache_bytes || 0)} gzipped` : "";
+        sub.textContent = `from cache · ${mb(st.gz_bytes || st.cache_bytes || 0)} gzipped`;
         bar.classList.remove("indet");
         bar.style.left = "0";
         bar.style.width = "90%";
+    } else {
+        // disabled, or server busy/frozen building natively — show "working"
+        msg.textContent = "Loading node definitions…";
+        sub.textContent = "";
+        bar.classList.add("indet");
+        bar.style.width = "35%";
     }
 }