Rust iOS Build

Build a Rust staticlib, expose a C header, package device and simulator slices as an XCFramework, and prove that a Swift consumer links and runs it.

Route neighbouring work to these skills, when they are installed:

• uniffi-packaging-versioning generates the header, modulemap, and Swift sources for a UniFFI core. This skill still owns the slices, the XCFramework, SwiftPM, and the checks.
• rust-swift-ffi owns the hand-written Swift wrapper, callbacks, and Swift concurrency isolation.
• rust-unsafe owns ABI layout and pointer ownership.
• rust-panic-safety owns panic containment at the exported C ABI and the panic profile setting.
• rust-native-linking owns build.rs, C dependencies, and linker inputs.
• rust-debugging investigates a crash after symbol preservation works.