chore: bump world-id-protocol crates to 0.12

[agentotto]

Summary

Bumps world-id-core and world-id-proof workspace dependencies from 0.11.0 to 0.12.0 in the root Cargo.toml.

Member crates (walletkit-core, walletkit-cli) already inherit these via workspace = true and required no changes.

Note: Cargo.lock was not updated — cargo update failed because 0.12.0 is not yet indexed on crates.io. Once the crate is published, run cargo update -p world-id-core -p world-id-proof locally and push the lock file update.

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Note

Medium Risk
Touches identity and ZK proof crates (including new provekit R1CS compiler wiring); behavior changes are possible even though WalletKit source is unchanged.

Overview
Raises the workspace pins for world-id-core and world-id-proof from 0.11.0 to 0.12.0 in the root Cargo.toml. Downstream crates that use workspace = true pick up the new versions without their own manifest edits.

Cargo.lock is refreshed for the whole World ID stack at 0.12.0, including transitive moves such as taceo-oprf 0.16.0, a new provekit-r1cs-compiler dependency on world-id-proof, and assorted itertools resolution updates in alloy/prost/taceo crates.

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