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/robosoft7

@@ -0,0 +1,25 @@
+language variant
+name Robosoft7
+echo 10 10000
+
+pitch 75 115
+
+formant 0 90 120 100
+formant 1 100 100 75
+formant 2 100 100 75
+formant 3 100 80 75
+formant 4 100 80 75
+formant 5 100 80 75
+formant 6 100 0 75
+formant 7 100 0 75
+formant 8 100 0 75
+
+roughness 0
+
+intonation 10
+voicing 150
+consonants 60 40
+stressLength 0 1 2 3 4 5 6 7
+stressAdd 130 140 140 100 0 0 130 160
+
+tone 100 255 600 70 1200 22 2000 66 3000 12