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/antonio

@@ -0,0 +1,21 @@
+language variant 
+name Antonio
+gender male
+
+pitch 82 128
+roughness 0
+
+formant 0 100  150 90
+formant 1 90  130 90
+formant 2 95  120 80
+formant 3 100  50 80
+formant 4 100  40 80
+formant 5 90  70 80
+formant 6 0  0 0
+formant 7 100  100 100
+formant 8 100  100 100
+voicing 150
+tone 600 255 1200 255 2000 80
+intonation 3
+stressLength 0 1 2 3 4 5 6 7
+stressAdd 130 140 140 100 0 0 130 160