Fix macOS release architecture verification

[SunChJ]

What changed

• fix the lipo -verify_arch argument order in the release workflow
• verify the built executable architecture in normal arm64 and x86_64 CI
• add an explicit, default-off recovery switch for publishing an existing immutable tag
• document how to recover a failed workflow without moving or recreating the tag

Root cause

The v0.8.0 arm64 and x86_64 builds completed, but both release jobs passed the input file after -verify_arch. Xcode 16.4 interpreted that path as an architecture flag and failed before codesign verification.

Validation

• swift test --parallel (171 tests)
• release build plus corrected lipo verification on arm64
• git diff --check
• workflow YAML parsing

The PR CI additionally exercises release builds and architecture verification on both macOS architectures.