Convert Settings, Invoices, IdlePrompt, AppTrackingPrompt, and
AppDiscard dialogs from animate-modal-enter CSS class to proper
<Transition name="modal"> wrappers for enter/leave animations.
Remove unused animate-modal-enter and animate-dropdown-enter keyframes.
Heading font: Plus Jakarta Sans (500/600/700) for all h1-h3, stat values, dialog titles, timer display, and wordmark.
Body font: Inter (400/500/600/700) unchanged but base bumped from 13px to 14px.
Mono font: JetBrains Mono replaces IBM Plex Mono for code and tabular data.