feat: security utilities

[Robert-MacWha]

Introduce security utilities for Kohaku common.

Currently Includes:

• Standard blocklist interface for seal / scamsniffer / metamask
• Address poisoning detector utility

[Robert-MacWha]

Open conversation for what should be in/out of scope. I'm generally following features raised in walletbeat's security features, the 1ts wallet security discussion, and the 1ts wallet security standard.

As a general rule, features should be in-scope if:

• Publicly-sourced (or from-chain). Wouldn't rely on a company's API, or wallet-internal state.
• Platform-agnostic
• Wallet-agnostic

And out-of scope if:

• UX-coupled (IMPORTANT)
• Informs wallet architecture decisions
• Requires persistent infrastructure (IE nodes, maintaining indexers, or hosting APIs).