fix: resolve WorldIDVerifier address from environment in proof commands

[kilianglas]

Summary

proof verify and proof test verified proofs on-chain against a single hardcoded WorldIDVerifier address (labeled "default: mainnet"). That address was actually the staging worldIDVerifier proxy.

This resolves the verifier address from the existing global --environment flag instead, via the shared resolve_environment helper that every other command already uses.

Changes

• walletkit-cli only: per-environment WorldIDVerifier proxies hardcoded in proof.rs, selected by --environment:
  • staging: 0x703a6316c975DEabF30b637c155edD53e24657DB
  • production: 0x00000000009E00F9FE82CfeeBB4556686da094d7
• proof verify/proof test default the verifier to the address for --environment; --verifier-address remains an optional override (also added to proof test for parity).
• Addresses sourced from world-id-protocol contracts/deployments/core/{staging,production}.json.

Kept entirely in walletkit-cli (no walletkit-core change) so CLI-tooling addresses don't widen the uniffi / Kotlin / Swift binding surface.