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/Gene

@@ -0,0 +1,17 @@
+language variant
+name Gene
+
+pitch  80 110
+
+formant 0 120 120 120
+formant 1 90 100 110
+formant 2 100 100 95
+formant 3 90 100 100
+formant 4 90 100 110
+formant 5 90 110 110
+formant 6 100 70 100
+formant 7 100 70 100
+formant 8 100 80 100
+voicing 120
+consonants 50 110
+