Add www-data/nobody to owner dropdown via _USER_WHITELIST

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -760,6 +760,7 @@ def set_permissions():
 # ===== GROUPS =====
 
 _GROUP_WHITELIST = {'root', 'staff', 'sambashare', 'www-data'}
+_USER_WHITELIST  = {'www-data', 'nobody'}   # system accounts useful as folder owners
 
 
 def _list_groups():
@@ -855,7 +856,8 @@ def _list_users():
             name, uid = parts[0], parts[2]
             uid = int(uid)
             if uid < 1000 or uid == 65534:
-                continue
+                if name not in _USER_WHITELIST:
+                    continue
             users.append({'name': name, 'uid': uid, 'smb': name in smb})
     return users