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/announcer

@@ -0,0 +1,17 @@
+name Half-LifeAnnouncementSystem
+language variant
+pitch 37 83
+klatt 4
+
+formant 1 88 100 100 0
+formant 2 96 100 100 0
+formant 3 98 100 100 0
+formant 4 96 100 100 0
+formant 5 100 100 100 0
+formant 6 100 100 100 0
+formant 7 100 100 100 0
+formant 8 100 100 100 0
+
+voicing 70
+consonants 70 70
+echo 154 26