ui: fix light mode — colori brand come testo + hover/focus adattivi
- Introdotte varianti --*-text (green/blue/purple/pink/amber/indigo/rec-red)
scure in light mode per contrasto AA su bg bianco
- Convertite le rule che usano brand colors come foreground (log, badge,
quota, footer, percent, info-row, update-status, save-status, toast,
beatport-status, colonna "già scaricato")
- Nav-item hover da #1A1A1A hardcoded → var(--bg-card-2)
- Input focus da #333 hardcoded → var(--bg-input-hover)
- Scrollbar thumb da #404040/#606060 hardcoded → var(--text-3)/var(--text-2)
- .hint code bg da rgba(255,255,255,0.08) → var(--bg-input)
- Table hover da rgba(99,102,241,0.06) → var(--bg-input) (visibile in light)
- .log .l-warn da #FDCB6E hardcoded → var(--amber-text)