fix(newos4): the virtual /sys entry leaked into listings, trees and counts (v4.6.88-90)

One phantom entry, three symptoms:
- ls() injected 'sys' whenever it was called without a path, so 'cd _agents; ls' advertised a
  sys directory that does not exist, and list_files('_agents/sys') answered 'Directory not
  found' — the reported false negative. Injection is now gated on dir === root.
- tree() pushed the same virtual name into the walk and dereferenced it, throwing mid-output on
  every root listing. Guarded.
- _gatherFileInfo() walked into /sys and counted a synthetic subtree: 146 files / 114 dirs for a
  44-file / 15-dir store. Virtual entries are skipped.

Verified: root still lists sys; _agents and skills do not; tree('') completes; world model total
(44) equals an independent walk of fs.root (44), agree: true.

1 files changed, 1 insertions, 1 deletions

diff --git a/modules/core/module-loader.js b/modules/core/module-loader.js
index 37212f3..95176d9 100644
--- a/modules/core/module-loader.js
+++ b/modules/core/module-loader.js
@@ -4,7 +4,7 @@
     // Core module bundle loaded synchronously in main.html.
     // This loader only handles version cache-busting, splash, terminal init, and optional ext modules.
 
-    const LATEST_VER = 'v4.6.87';
+    const LATEST_VER = 'v4.6.90';
     const CACHE = '?v=' + LATEST_VER;
     const stored = localStorage.getItem('webx11_cache_ver');
     if (stored !== LATEST_VER) {