design overhaul + expenses page
- Stripe-style theme: single indigo (#635BFF) brand, 6px radius,
Inter scale; rewritten themePrimitives + MUI customizations
(solid primary, near-black secondary, severity-aware Alert)
- Sticky Header (brand-left nav, theme toggle, mobile drawer),
inline Footer, route fade-in, per-route document.title
- Home hero + feature cards (dead /dashboard,/reports links replaced)
- Split-panel AuthPage with validation and password visibility
- Data pages: PageHeader/EmptyState, breadcrumbed Fetch Request
pages, admin table polish (numeric alignment, row-hover actions,
skeletons, empty states), single-accent admin SideMenu
- Global ToastProvider wired into app shell
- New /expenses page: month-grouped feed, single-open accordion
with inline detail (account, tags, amount, timestamps)