Implement Ledger hardware wallet USB/HID communication

[ch4r10t33r]

Description

Complete Ledger hardware wallet with USB/HID communication.

Location

• File: src/signer/ledger.zig
• Lines: 143, 165, 179, 192, 209-210, 227, 248

Current Status

Complete framework, no hardware communication.

Tasks

• Implement USB/HID connection
• Implement APDU protocol
• Open Ethereum app
• Get address from device
• Sign transactions with confirmation
• Sign messages (personal_sign)
• Sign EIP-712 typed data
• Device detection
• Error handling
• Tests with mock device

Priority

Medium - For security-conscious apps

References

• Ledger docs: https://developers.ledger.com/