💳 Invoicing & Receipting 📊 | Trend‑Driven Health Product Catalogs 🛍️ + Customer Engagement 🤝

Finalized Catalog, Invoice, and Immutable Receipt Schemas

Ensuring data integrity • Immutable receipts • Compliance with GDPR and Kenya DPA

📦 Catalog Schema • 🧾 Invoice Schema • 📜 Immutable Receipt • 🔒 Data Integrity • ⚖️ Compliance • 🛠️ PostgreSQL