newOS4 v4.6.18: nginx dav trailing-slash semantics

Discovered by dav-health-check.sh E2E (10/10 pass now):
- nginx dav module REQUIRES trailing slash on MKCOL (no-slash → 409)
  and on directory DELETE (no-slash → 409/404); existing dir + slash
  MKCOL → 405 (the real 'already exists' signal)
- _normalizeRemotePath now PRESERVES trailing slashes (collection ops)
- _ensureDir MKCOLs with trailing slash
- _deleteFile retries with slash on 409/404 (collection delete)
- health-check expectations corrected (405 = existing, slash required)

1 files changed, 1 insertions, 1 deletions

diff --git a/modules/core/module-loader.js b/modules/core/module-loader.js
index 16723ad..ef3e2ee 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 = 'v4.6.16';
+    const LATEST_VER = 'v4.6.18';
     const CACHE = '?v=' + LATEST_VER;
     const stored = localStorage.getItem('webx11_cache_ver');
     if (stored !== LATEST_VER) {