Function Fn 

pub async fn Fn(
    BinaryDir: &PathBuf,
) -> Result<Option<HashMap<String, ExtensionDescriptionStateDTO>>, CommonError>

Try to load extension descriptors from the pre-baked manifest cache.

Probes two locations in order:

1. BinaryDir/extensions.manifest.json - dev binary next to repo cache
2. BinaryDir/../Resources/extensions.manifest.json - .app bundle path (tauri.conf.json copies Sky/Target/extensions.manifest.json there)

Bundled caches skip the stale check: they were written at build time and are always consistent with the extensions packed into the same .app.

Returns Ok(Some(map)) on a cache hit, Ok(None) when the cache is missing/stale/incompatible, and Err(_) only on unexpected I/O errors.