feat: implement side-channel timing attack detection

[oritwoen]

Description

Detect timing-based side-channel leaks in ECDSA signatures.

Background

Variable-time scalar multiplication leaks information about nonce bits through timing. With enough timing measurements, lattice attacks can recover the private key.

Requirements

• Accept timing metadata with signatures
• Statistical analysis of timing variations
• Correlate timing with nonce bit patterns
• Integrate with HNP/lattice recovery

Priority

Low - Requires additional metadata (timing measurements) not typically available from blockchain data alone.

Technical Notes

• Primarily useful for active attacks, not historical analysis
• May be more relevant for hardware security research
• Consider as optional/experimental feature