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/voices/!v/travis

@@ -0,0 +1,23 @@
+language variant
+name travis
+gender male 30
+
+pitch 75 120
+
+formant 0 90 90 90 90 
+formant 1 50 100 80 95
+formant 2 90 60 90 100
+formant 3 80 80 90 100
+formant 4 50 90 100 100
+formant 5 100 95 100 55
+formant 6 80 50 100 85
+formant 7 60 60 60 120
+formant 8 80 80 140 100
+
+tone 600 100 1000 200 1500 50 
+flutter 1 
+
+roughness 3 
+
+voicing 200 
+consonants 120 190