Lumina node UniFFI

Deprecated: iOS and Android CI, release automation, and binary artifact builds have been removed as of #960. The only production consumer (Leap wallet) is sunsetting on May 28, 2026, and no other production consumers were identified. The UniFFI code remains in the repository for now but the builds will be removed in future versions.

A UniFFI layer for the Lumina node to interact with it from Swift and Kotlin