Support Debug Swift builds

[ketzusaka]

This introduces build profiles for the Swift package that walletkit produces. A --debug flag can now be passed to the build system to produce a framework with debug symbols. This allows us to attach with LLDB and step through the real code, and reduces the iteration cycle for testing new functionality directly in the iOS app.

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Note

Low Risk
Build-tooling only; default release behavior is unchanged except for threading a profile parameter through existing steps.

Overview
Adds Release vs Debug build profiles for the iOS XCFramework pipeline. Release keeps the existing optimized build (--release, dead-strip link flags, release artifact paths). Debug builds unoptimized with symbols preserved (no --release, no dead-strip flags, debug paths) so LLDB can step through Rust in the iOS app.

The shared build::run path now takes a Profile and uses it for RUSTFLAGS, cargo build, universal lipo, UniFFI binding generation, and slice paths. swift local accepts --debug to pick the debug profile; swift build and swift test still always use release.

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