add readable and writable traits for signal-like structs

packages/signals/src/lib.rs

@@ -16,6 +16,9 @@ pub use selector::*;
 pub(crate) mod signal;
 pub use signal::*;
 
+mod read_only_signal;
+pub use read_only_signal::*;
+
 mod dependency;
 pub use dependency::*;
 
@@ -30,3 +33,9 @@ pub use global::*;
 
 mod impls;
 pub use generational_box::{Storage, SyncStorage, UnsyncStorage};
+
+mod read;
+pub use read::*;
+
+mod write;
+pub use write::*;