Add libsodium-dev to Docker build images and configure Windows cross-build
environment to fix CI build failures on all platforms (Linux amd64/arm64,
Windows amd64). Failures were caused by missing libsodium dependency
required by tauri-plugin-stronghold → iota-crypto → libsodium-sys-stable.
Changes:
- Install libsodium-dev in Linux amd64 and arm64 Docker images
- Set SODIUM_LIB_DIR and SODIUM_STATIC env vars for Windows cross-build
- Add smoke test to verify libsodium linking via stronghold dependency
- Add comprehensive test coverage (3 new tests in state module)
All 802 tests pass (416 Rust + 386 TypeScript). Zero linting warnings.
Fixes: Linux "libsodium not found via pkg-config" error
Fixes: Windows "SODIUM_LIB_DIR incompatible with SODIUM_USE_PKG_CONFIG" error
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>