feat: prepare published paykit ios sdk for qa

[ovitrif]

Description

• Adds preparation of the published Paykit rc73 iOS SDK with revision and archive checksum verification. It links the Swift bindings for device and simulator so QA can use the SDK without requiring an installable companion app.
• The review stack's test environment runs this change; the test run that needs it is reported in a comment here.
• Checked: The helper downloaded the published archive and verified its SwiftPM SHA256, then linked the upstream Swift binding fixtures for both iOS slices. Its corruption check passed, and a repeat invocation verified the cached artifact. Upstream FFI checks passed 131 unit and 4 integration tests with 2 Docker-dependent tests excluded after failing because Docker Postgres was unavailable.

Out of Scope

• QA item N6 and app dependency changes
• Docker-dependent upstream integration tests

[ovitrif]

Closing: synonymdev/bitkit-ios#914 was tested without it, so it is not needed.