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/Marco

@@ -0,0 +1,23 @@
+language variant
+name Marco
+gender male 30
+intonation 1
+pitch  100 152
+echo 50 80
+flutter 2
+roughness 0
+stressAmp 25 25  24 20  38 31  39 27
+stressAdd 250 125 250 250 225 145 50 256
+
+formant 0 100 120 130
+formant 1 75 180 170
+formant 2 92 120 110
+formant 3 140 120 110
+formant 4 10 20 20 -50
+formant 5 110 70 20
+formant 6 140 100 98
+formant 7 130 120 115
+formant 8 105 120 108
+voicing 38
+consonants 90 140
+tone 420 150 1200 135 3000 70 4700 40