Fix dark mode inconsistencies across all pages
Add missing dark: variant classes to:
- consent_prompt, check_live/form_component: modal overlays
- error pages (404, 500): body background
- marketing_layouts: page background
- home page: pricing card, CTA button, feature card
- totp_enrollment: QR container
- admin audit_live/monitoring_live: badge colors, event borders
- alert_live: acknowledged-by text
- dashboard_live: severity color fallback
- device_live (index, show, form): status text, spinners
- settings_live: checkbox borders
- trace_live: status colors, labels, table headers
Graham McIntie
7ec2b2a00a