- Create types.ts with proper TypeScript interfaces for dashboard data
- Replace all 'any' types in dashboard/page.tsx with DashboardStats and RecentInvoice
- Fix type safety in invoice-form.tsx:
- Replace 'any' in updateItem with proper union type
- Add generic type parameter to updateField for type safety
- Fix status type assertion (any -> proper union type)
- Replace || with ?? for safer null handling
- All TypeScript compilation errors resolved
- Lint down to 1 warning (false positive for 'loading' variable)