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/whisperf

@@ -0,0 +1,24 @@
+language variant
+name female_whisper
+gender female
+
+pitch 160 220
+roughness 3
+
+formant 0 105   0 150
+formant 1 110  40 160
+formant 2 110  70 150
+formant 3 110  70 150
+formant 4 115  80 150
+formant 5 115  80 150
+formant 6 110  70 150
+formant 7 110  70 150
+formant 8 110  70 150
+
+stressAdd 0 0 -10 -10 0 0 10 40
+
+// whisper
+voicing 20
+breath 75 75 50 40 15 10
+breathw 150 150 200 200 400 400
+