Implement Bitcoin payment integration

[b0ase]

Description

Add native Bitcoin payment capabilities across all applicable Bitcoin OS applications.

Features

• Bitcoin wallet integration
• Lightning Network support
• Payment processing
• Transaction history
• Multi-currency support (BTC, BCH, BSV)
• Invoice generation
• Payment notifications

Affected Apps

• Bitcoin Exchange
• Bitcoin Shares
• Bitcoin CRM
• Bitcoin Writer (subscriptions)
• Bitcoin Education (courses)

Priority

High - Core functionality for Bitcoin OS