Add visionOS support to the binary distribution #1180

Summary

OpenSwiftUI-spm distributes XCFrameworks for iOS and macOS. Its binaries do not include visionOS device or simulator slices, and its package manifests and Tuist Example do not declare visionOS support.

Scope

• Include visionOS device and simulator slices in the OpenSwiftUI binary packaging workflow.
• Configure the UIKit header overlay and visionOS-capable runners for packaging.
• Update OpenSwiftUI-spm's Package.swift and release template for visionOS.
• Add visionOS to the binary package's Tuist Example and document the binary requirements.

Acceptance criteria

• The packaging workflow includes visionOS device and simulator slices in all seven distributed XCFrameworks.
• OpenSwiftUI-spm's manifest and template declare consistent visionOS platform support.
• The Example project includes an Apple Vision destination with a visionOS 2.0 deployment target.

Related to #1171.