Simplify hook runtime state

Remove the unused pending-hook layer and dead protocol trait wrappers, and resolve active hooks through a direct active-only flow with peer-side indexing instead of scan-based recovery.

src/protocol/tree/mod.rs

@@ -8,7 +8,7 @@ pub use endpoint::{
     ChildRoute, ConnectionState, Endpoint, EndpointError, EndpointOutcome, Ingress, LeafSpec,
     LocalEvent, ProtocolEndpoint,
 };
-pub use hook::{ActiveHook, HookConflict, HookKey, HookTable, PendingHook};
+pub use hook::{ActiveHook, HookConflict, HookKey, HookTable};
 pub use routing::{
     DefaultRouteProvider, LeafNode, RouteDecision, RouteProvider, TreeNode, is_prefix,
     route_destination,