move state types from signed_core into signed_state

docs/push-refactor.md

@@ -46,8 +46,16 @@ pub enum GitPushMode {
     Main,
 }
 
+/// A git ref with the commit it points at.
+pub struct GitRef {
+    /// Full ref name, like `refs/heads/main` or `refs/tags/v1.0`.
+    pub name: String,
+    /// Commit id, `bitcoin_hashes::sha1::Hash`, the type NIP-34 tags carry.
+    pub commit: Sha1Hash,
+}
+
 pub struct SyncState {
-    pub refs: Vec<(String, String)>,
+    pub refs: Vec<GitRef>,
     pub head: Option<String>,
     /// Local repository to push from; `None` for states parsed from events.
     pub path: Option<PathBuf>,