fix(l1): ignore unknown protocols in capability exchange

[MegaRedHand]

Motivation

Failing due to a peer having extra capabilities can make us lose exceptional peers. Hence, we want to ignore any extra capabilities they have.

Description

This PR changes Capability.protocol to be an 8-byte array instead of a string, allowing us to store any string we receive.

[github-actions]

Lines of code report

Total lines added: 44
Total lines removed: 9
Total lines changed: 53

Detailed view

+---------------------------------------------+-------+------+
| File                                        | Lines | Diff |
+---------------------------------------------+-------+------+
| ethrex/crates/networking/p2p/rlpx/p2p.rs    | 312   | +44  |
+---------------------------------------------+-------+------+
| ethrex/crates/networking/rpc/admin/peers.rs | 103   | -9   |
+---------------------------------------------+-------+------+

[Copilot]

Pull Request Overview

This PR refactors how protocol identifiers are stored and matched, switching from strings to fixed-size byte arrays to allow unknown protocols to be ignored rather than causing failures.

• Changed Capability.protocol from &'static str to [u8; 8] with padding
• Updated all matching sites to call the new protocol() method
• Added helper pad_right, updated RLP (de)serialization, and new decode tests

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
crates/networking/rpc/admin/peers.rs	Switched to calling cap.protocol() and refactored test setup to use Capability::eth() and snap()
crates/networking/p2p/rlpx/p2p.rs	Introduced pad_right, changed protocol field to [u8; 8], updated RLP (de)serialization, and added tests
crates/networking/p2p/rlpx/connection/server.rs	Updated server match clauses to use the new protocol() accessor

Comments suppressed due to low confidence (1)

crates/networking/p2p/rlpx/p2p.rs:346

• You might add a test for decoding an unknown protocol (e.g., a custom >8-byte name) to verify that the code correctly stores arbitrary bytes and handles invalid lengths.

    fn test_decode_capability() {