Some bugs during demo development

[insipx]

• fix bug where we generated two wallets in methods & gateway context leading to insufficient funds error
• use correct signer wallet in endpoints wallet_address and balance
• add a registry-localnet binary that launches an anvil instance with the registry already deployed. Useful for local testing E2E with libxmtp, without touching Sepolia
• generally add some more logging, especially around gas price use when calling the DIDRegistry contract

[codecov[bot]]

Codecov Report

Attention: 14 lines in your changes are missing coverage. Please review.

Comparison is base (18f851d) 91.16% compared to head (938199d) 89.86%.

Files	Patch %	Lines
registry/src/lib.rs	33.33%	10 Missing :warning:
lib-xps/src/lib.rs	0.00%	2 Missing :warning:
xps/src/main.rs	80.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #66 +/- ## ========================================== - Coverage 91.16% 89.86% -1.31% ========================================== Files 12 12 Lines 419 444 +25 ========================================== + Hits 382 399 +17 - Misses 37 45 +8 ```

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[insipx]

It's already merged but would like to point out that registry-localnet could be renamed to localnet because we might add more deployed smart contracts there. otherwise lgtm

I actually gotta do a follow up anyway because i screwed up the DID_REGISTRY address, good callout!