Deduplicate Swift package manifest variants in the cache registry

Fresh tuist install runs in new worktrees no longer fail with SwiftPM “duplicate key found” errors for Package@swift-X.Y.swift manifests. The cache registry now treats alternate Swift package manifests by their canonical Swift tools version, so a default Package.swift and an alternate manifest that resolve to the same tools version (e.g. 6 == 6.0 == 6.0.0) are no longer both advertised, stored, or returned in the registry response. This unblocks the dependency resolution step before tuist generate and focused CLI builds and tests. The same canonicalization is applied to live registry responses, newly indexed release metadata, and the S3 metadata fallback path.