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, 5 insertions, 0 deletions

diff --git a/modules/core/module-world-model.js b/modules/core/module-world-model.js
index 54a17e4..6e8f3c3 100644
--- a/modules/core/module-world-model.js
+++ b/modules/core/module-world-model.js
@@ -203,6 +203,11 @@ class WorldModelModule {
             const entries = fs.ls(path);
             if (!entries) return;
             for (const e of entries) {
+                // /sys is synthesized by ls() on demand and has no node behind it. Walking into it
+                // counted a synthetic subtree (114 dirs / 146 files in a store that holds 43 files),
+                // which is the "the counts disagree" report: two different populations were both
+                // printed as "files".
+                if (e._virtual) continue;
                 if (e.type === 'file') fileCount++;
                 else { dirCount++; walk(path === '/' ? '/' + e.name : path + '/' + e.name); }
             }