DocC builds work with SPM targets that import sibling package targets

DocC builds for generated Tuist projects now succeed on SwiftPM targets whose public Objective-C headers import another package target without an explicit Package.swift dependency edge. When a header imports a sibling target, Tuist derives the missing build dependency from concrete #import / #include statements, and framework module maps are copied to the canonical Modules/module.modulemap location so Clang ExtractAPI can locate them. Cases like FirebaseCoreExtension publicly importing FirebaseCore now compile their DocC archives without the no module map error.