Nested static-ObjC xcframeworks (ARCore) consumed via their own module map

Cached static Objective-C xcframeworks with a “nested” layout, where the module map and headers live in a Headers// subdirectory and the headers re-import each other using <Module/Header.h> prefixes (notably Google’s ARCoreGARSession / ARCoreGeospatial), are now consumed via the xcframework’s own module map and the Headers root as HEADER_SEARCH_PATHS, so the module is defined exactly once and the prefixed sibling imports resolve. Flat-layout static xcframeworks keep their previous behavior unchanged.