release(v3.5.2): relax username validation + stdClass namespace fix

- users(core): allow dots/@ in usernames and block "." / ".." to prevent path-like edge cases
- php(core): namespace stdClass return to \stdClass for consistency under FileRise\Domain
- admin: update sponsor list (add Stefan)

CHANGELOG.md

@@ -1,5 +1,31 @@
 # Changelog
 
+## Changes 02/26/2026 (v3.5.2)
+
+`release(v3.5.2): relax username validation + stdClass namespace fix`
+
+**Commit message**  
+
+```text
+release(v3.5.2): relax username validation + stdClass namespace fix
+
+- users(core): allow dots/@ in usernames and block "." / ".." to prevent path-like edge cases
+- php(core): namespace stdClass return to \stdClass for consistency under FileRise\Domain
+- admin: update sponsor list (add Stefan)
+```
+
+**Changed**  
+
+- **Username validation**
+  - Updated `REGEX_USER` to allow `.` and `@` in usernames (and spaces/underscores/dashes as before).
+  - Added a negative lookahead to reject `.` and `..` as standalone usernames.
+- **PHP namespace correctness**
+  - `UserModel::getUserPermissions()` now returns `\stdClass` (global) instead of `stdClass` to avoid namespace resolution issues under `FileRise\Domain`.
+- **Admin sponsor page**
+  - Added “Stefan” to the sponsors list in `public/js/adminSponsor.js`.
+
+---
+
 ## Changes 02/19/2026 (v3.5.1)
 
 `release(v3.5.1): authenticated Link File deep links + shared file request mode`

config/config.php

@@ -43,7 +43,7 @@ define('TOTAL_UPLOAD_SIZE','5G');
 define('REGEX_FOLDER_NAME','/^(?!^(?:CON|PRN|AUX|NUL|COM[1-9]|LPT[1-9])$)(?!.*[. ]$)(?:[^<>:"\/\\\\|?*\x00-\x1F]{1,255})(?:[\/\\\\][^<>:"\/\\\\|?*\x00-\x1F]{1,255})*$/xu');
 define('PATTERN_FOLDER_NAME','[\p{L}\p{N}_\-\s\/\\\\]+');
 define('REGEX_FILE_NAME', '/^[^\x00-\x1F\/\\\\]{1,255}$/u');
-define('REGEX_USER',       '/^[\p{L}\p{N}_\- ]+$/u');
+define('REGEX_USER',       '/^(?!\.{1,2}$)[\p{L}\p{N}_\- .@]+$/u');
 define('FR_DEMO_MODE', false);
 
 date_default_timezone_set(TIMEZONE);

public/js/adminSponsor.js

@@ -35,7 +35,8 @@ const DEFAULT_SUPPORTERS = [
   '@jubnl',
   'Juozaitis S',
   'Cocoseb31',
-  'nulltrope'
+  'nulltrope',
+  'Stefan'
 ];
 
 /**

src/FileRise/Domain/UserModel.php

@@ -420,7 +420,7 @@ class UserModel
             }
         }
 
-        return new stdClass();
+        return new \stdClass();
     }
 
     /**