switch safe-eth-py dep to patched version and rename Safe API auth arg

[wavey0x]

• support env variable name that matches what's called for in safe-eth-py
• point to patched safe-eth-py which:
  • preserves eth-brownie requirement that web3 be version <7.0.0
  • resolves base_url based on new Safe transaction service URLs
  • resolves AttributeError: 'LocalAccount' object has no attribute 'signHash'

[banteg]

is there a better way than to rely or wavey backport? basically we are blocked by different web3 py requirement between brownie and safe-eth-py?

[banteg]

Yes, basically.

• eth-brownie 1.20.7 wants web3>=6,<7
• the last upstream safe-eth-py release on that line is v6.4.0
• upstream safe-eth-py v7+ moved to web3>=7, so we can't just consume the newer upstream fixes while staying on Brownie

There's also a separate break on the old line: safe-eth-py v6.4.0 still uses signHash, but current eth-account uses unsafe_sign_hash, so v6.4.0 can fail even with web3 6.

One nuance: the old safe-transaction-*.safe.global hosts still redirect to api.safe.global, so the hostname move by itself is not the hard blocker. The real blocker is that the useful Safe tx-service/auth fixes now live on the post-web3 7 line, while Brownie is still pinned to pre-web3 7.

So the practical options are:

1. keep a minimal pre-web3 7 backport/fork for the needed fixes
2. vendor those small patches locally in brownie-safe
3. move off Brownie / wait for a web3 7-capable stack

If we keep the fork, we should pin an exact commit/tag instead of a mutable branch.