apple_framework, apple_application, and apple_test_bundle are now real build rules

The previously schema-only bundle rules now run real build actions. apple_framework emits a dylib, swiftmodule, and modulemap. apple_application compiles and links a Mach-O executable, embeds dependent frameworks, and generates a signed .app bundle. apple_test_bundle produces a loadable .xctest bundle linked against XCTest. The implementation also rejects unsupported attributes on these rules with clear errors.