radicle: introduce specialised Stream types

Add type aliases to specialise the `Stream` type for each of `Patch`, `Issue`,
and `Identity`.

An `init` constructor is also added for each to make it easier to construct each
stream.

crates/radicle/src/cob/identity.rs

@@ -12,6 +12,7 @@ use thiserror::Error;
 use crate::identity::doc::Doc;
 use crate::node::device::Device;
 use crate::node::NodeId;
+use crate::storage;
 use crate::{
     cob,
     cob::{
@@ -38,6 +39,15 @@ pub type Op = cob::Op<Action>;
 /// Identifier for an identity revision.
 pub type RevisionId = EntryId;
 
+pub type IdentityStream<'a> = cob::stream::Stream<'a, Action>;
+
+impl<'a> IdentityStream<'a> {
+    pub fn init(identity: ObjectId, store: &'a storage::git::Repository) -> Self {
+        let history = cob::stream::CobRange::new(&TYPENAME, &identity);
+        Self::new(&store.backend, history, TYPENAME.clone())
+    }
+}
+
 /// Proposal operation.
 #[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize)]
 #[serde(tag = "type")]

crates/radicle/src/cob/issue.rs

@@ -19,6 +19,7 @@ use crate::identity::doc::DocError;
 use crate::node::device::Device;
 use crate::node::NodeId;
 use crate::prelude::{Did, Doc, ReadRepository, RepoId};
+use crate::storage;
 use crate::storage::{HasRepoId, RepositoryError, WriteRepository};
 
 pub use cache::Cache;
@@ -33,6 +34,15 @@ pub static TYPENAME: LazyLock<TypeName> =
 /// Identifier for an issue.
 pub type IssueId = ObjectId;
 
+pub type IssueStream<'a> = cob::stream::Stream<'a, Action>;
+
+impl<'a> IssueStream<'a> {
+    pub fn init(issue: IssueId, store: &'a storage::git::Repository) -> Self {
+        let history = cob::stream::CobRange::new(&TYPENAME, &issue);
+        Self::new(&store.backend, history, TYPENAME.clone())
+    }
+}
+
 /// Error updating or creating issues.
 #[derive(Error, Debug)]
 pub enum Error {

crates/radicle/src/cob/patch.rs

@@ -46,6 +46,15 @@ pub type Op = cob::Op<Action>;
 /// Identifier for a patch.
 pub type PatchId = ObjectId;
 
+pub type PatchStream<'a> = cob::stream::Stream<'a, Action>;
+
+impl<'a> PatchStream<'a> {
+    pub fn init(patch: PatchId, store: &'a storage::git::Repository) -> Self {
+        let history = cob::stream::CobRange::new(&TYPENAME, &patch);
+        Self::new(&store.backend, history, TYPENAME.clone())
+    }
+}
+
 /// Unique identifier for a patch revision.
 #[derive(
     Wrapper,