feat: improve world app siwe handling

[paolodamico]

We don't need a safe smart account for world app SIWE.

---

Note

Medium Risk
Changes the World App SIWE message construction to depend on EoaSigner (EOA address) instead of SafeSmartAccount, affecting authentication/signature flows and address selection.

Overview
World App SIWE message creation now takes an EoaSigner instead of a SafeSmartAccount, and sets the message address directly from the EOA signer (removing the smart-account dependency for this flow).

Adds convenience accessors returning BedrockAddress (SiweMessage::address() and EoaSigner::address()), and updates SIWE tests to construct/use EoaSigner and validate EOA-recoverable signatures for the World App backend flow.

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[chatgpt-codex-connector]

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