Implement Peer Permissioning for Discovery v5

[Gabriel-Trintinalia]

Description

Peer permissioning via AddressAccessPolicy is not currently enforced for discv5-discovered peers.

Scope

• Apply AddressAccessPolicy checks to discv5 peer candidates
• Ensure rejected peers are filtered early in the discovery pipeline
• Align behaviour with existing discv4 permissioning semantics, where permissioning is limited to IP-based filtering. Discv5 does not support peer ID–level filtering.

Acceptance Criteria

• Disallowed peers are never promoted to active connections