Add Solana base58 key support to Python validation scripts

[Copilot]

Pull Request Checklist

Before submitting this PR, please make sure:

• You have run cargo clippy and addressed any warnings
• You have added appropriate tests (if applicable)
• You have updated the documentation (if applicable)
• You have reviewed your own code
• You have updated changelog (if applicable)

Description

Senate key validation and multisig derivation scripts now support both Substrate SS58 and Solana base58 key formats through automatic detection.

Changes

Enhanced key format detection:

• is_solana_key(): Multi-step validation distinguishing SS58 (network prefix + checksum) from Solana (plain base58)
• Checks: character prefix heuristics → base58 decode → SS58 validation attempt
• Returns Solana if base58 decodes to exactly 32 bytes but fails SS58 validation

Universal key decoding:

• decode_key() / decode_key_to_hex(): Handle both formats, return 32-byte Ed25519 public key
• Solana: Direct base58 decode
• SS58: ss58_decode → hex → bytes

Updated scripts:

• validate_replacement_key.py: Added format column to validation table
• derive_senate_multisig.py: Multisig derivation works with mixed key types
• Both scripts remain self-contained with duplicated helper functions

Documentation:

• Updated help text with format examples
• Added dependency: base58 package

Example

# Both formats work interchangeably
senate_keys = [
    "5H47pSknyzk4NM5LyE6Z3YiRKb3JjhYbea2pAUdocb95HrQL",  # SS58
    "7EqQdEULxWcraVx3mXKFjc84LhCkMGZCkRuK3wxXkVSu",      # Solana
]

# Scripts auto-detect format, decode to same 32-byte result
for key in senate_keys:
    decoded = decode_key(key)  # Returns 32 bytes for both

Backward compatible. Existing SS58 keys work unchanged.

Related Issues

N/A

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• astral.sh
  • Triggering command: /usr/bin/curl curl -LsSf REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

make this work with solana keys

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