Harden patch resolution and offline validation

[coconutbird]

Summary

• harden Far Cry 2 patch resolution with Portex-validated PE sections, guarded signatures, transactional writes, rollback, and idempotency
• add optional patch configuration, diagnostics, known-build handling, and an offline Dunia.dll integration test under Cargo's tests/ layout
• update cppvtable, replace the high-level windows crate with windows-sys, and remove the unmaintained paste dependency
• replace Cargo Husky with prek and let the repository provision its Rust toolchain and development tools

Validation

• prek run --all-files
• cargo build --locked --release
• offline validation against Steam 1.03 Dunia.dll without loading, executing, or modifying the game DLL
• all five patch groups resolved and applied idempotently to a disposable in-memory image