Agregar campo username a User entity y DTO

- Columna username (unique, nullable) en auth.users
- Campo username en CreateUserDto y UpdateUserDto

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tts/piper/espeak-ng-data/lang/sit/yue

@@ -0,0 +1,13 @@
+name Chinese (Cantonese)
+language yue
+language zh-yue
+language zh 8
+
+phonemes yue
+dictionary yue
+
+// interpret English letters as 1=English words, 2=jyutping
+dictrules 1
+
+words 1
+dict_min 10000