Multi-User Smart Billing App

I need a lean, working MVP that lets me create bills by voice and instantly share a PDF on WhatsApp while storing every transaction in a central database.

Core flow
1. The user (Admin, Manager, or Customer) taps a mic icon, speaks item names and amounts, and the app converts the speech to text in English, Hindi, or Hinglish.
2. A clean bill preview appears, ready to save as PDF.
3. With one tap the PDF is sent through the device’s native WhatsApp share sheet.
4. Each bill, user, and role-based action is written to a cloud database so basic reporting is possible later.

Key requirements
• Platforms: Android and iOS from a single codebase (Flutter, React Native, or similar—open to your recommendation).
• Roles: Admin can see everything, Manager sees team activity, Customer only sees personal bills.
• Lightweight login (mobile number + OTP or similar).
• Simple dashboard listing recent bills with search/filter.
• Source code, build instructions, and a brief setup guide delivered on hand-off.

Keep the UI straightforward; focus effort on accurate speech-to-text, reliable PDF generation, and WhatsApp sharing. Once those pillars are solid I can layer on extras in a later phase.