Per-route selection of registered lifecycle hooks.

ServerConfig.lifecycle_hooks holds Arc<dyn LifecycleHook> function pointers and is marked #[serde(skip)] / #[alef(skip)] because closures cannot be serialized or cross the FFI boundary. A per-route field with that same shape would be invisible to alef, and therefore invisible to every binding — defeating the purpose of exposing it here. This descriptor carries [LifecycleHookRef] entries instead: each one names a registered hook (plus its declared dependencies and optional config), so a later enforcement phase can resolve those names against the server's registered LifecycleHooks and run the matches for this route. The five fields mirror the five hook phases documented in the tower-middleware-and-lifecycle project convention (onRequest, preValidation, preHandler, onResponse, onError).