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, 5 insertions, 4 deletions

diff --git a/scripts/test-webdav-paths.mjs b/scripts/test-webdav-paths.mjs
index a8340c0..d75f9f6 100644
--- a/scripts/test-webdav-paths.mjs
+++ b/scripts/test-webdav-paths.mjs
@@ -57,7 +57,7 @@ function check(name, cond, got) {
         // relative + traversal + dupes:
         ['./a//b/../c.txt', '/a/c.txt'],
         ['/a/b/../../d.txt', '/d.txt'],
-        ['/skills/', '/skills'],
+        ['/skills/', '/skills/'],  // trailing slash PRESERVED (nginx dav collection ops need it)
         ['backups', '/backups'],
         // foreign space stays intact (only own space prefix is stripped):
         ['/spaces/otheruser/file.txt', '/spaces/otheruser/file.txt'],
@@ -90,8 +90,8 @@ function check(name, cond, got) {
     };
     m._listDir = async () => { throw new Error('ENOENT'); };
     await m._ensureDir('https://webx11.duckdns.org/spaces/mindtech/thaimassage-kiefersfelden');
-    check('_ensureDir MKCOLs normalized path (no https:/ junk)',
-          mkcols.length === 1 && mkcols[0] === '/thaimassage-kiefersfelden', mkcols);
+    check('_ensureDir MKCOLs normalized path (no https:/ junk, trailing slash for nginx)',
+          mkcols.length === 1 && mkcols[0] === '/thaimassage-kiefersfelden/', mkcols);
 
     // Existing dir fast-path: __list__ probe succeeds -> no MKCOL at all
     const m2 = makeMod();
@@ -107,7 +107,8 @@ function check(name, cond, got) {
     m3._listDir = async (p) => { if (p === '/backups') return []; throw new Error('ENOENT'); };
     m3._webdavRequest = async (method, path) => { if (method === 'MKCOL') mkcols3.push(path); return { ok: true, status: 201 }; };
     await m3._ensureDir('/backups/2026');
-    check('_ensureDir MKCOLs only missing tail', mkcols3.length === 1 && mkcols3[0] === '/backups/2026', mkcols3);
+    check('_ensureDir MKCOLs only missing tail (trailing slash for nginx)',
+          mkcols3.length === 1 && mkcols3[0] === '/backups/2026/', mkcols3);
 }
 
 // --- PUT via _webdavRequest hits normalized URL ---