Separate repository state synchronization from worktree synchronization (#27140)

This PR updates our DB schemas and wire protocol to separate the
synchronization of git statuses and other repository state from the
synchronization of worktrees. This paves the way for moving the code
that executes git status updates out of the `worktree` crate and onto
the new `GitStore`. That end goal is motivated by two (related) points:

- Disentangling git status updates from the worktree's
`BackgroundScanner` will allow us to implement a simpler concurrency
story for those updates, hopefully fixing some known but elusive bugs
(upstream state not updating after push; statuses getting out of sync in
remote projects).
- By moving git repository state to the project-scoped `GitStore`, we
can get rid of the duplication that currently happens when two worktrees
are associated with the same git repository.

Co-authored-by: Max <max@zed.dev>

Release Notes:

- N/A

---------

Co-authored-by: Max <max@zed.dev>
Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/proto/src/proto.rs

@@ -445,6 +445,8 @@ messages!(
     (UpdateUserPlan, Foreground),
     (UpdateWorktree, Foreground),
     (UpdateWorktreeSettings, Foreground),
+    (UpdateRepository, Foreground),
+    (RemoveRepository, Foreground),
     (UsersResponse, Foreground),
     (GitReset, Background),
     (GitCheckoutFiles, Background),
@@ -573,6 +575,8 @@ request_messages!(
     (UpdateParticipantLocation, Ack),
     (UpdateProject, Ack),
     (UpdateWorktree, Ack),
+    (UpdateRepository, Ack),
+    (RemoveRepository, Ack),
     (LspExtExpandMacro, LspExtExpandMacroResponse),
     (LspExtOpenDocs, LspExtOpenDocsResponse),
     (SetRoomParticipantRole, Ack),
@@ -689,6 +693,8 @@ entity_messages!(
     UpdateProject,
     UpdateProjectCollaborator,
     UpdateWorktree,
+    UpdateRepository,
+    RemoveRepository,
     UpdateWorktreeSettings,
     LspExtExpandMacro,
     LspExtOpenDocs,
@@ -783,6 +789,31 @@ pub const MAX_WORKTREE_UPDATE_MAX_CHUNK_SIZE: usize = 2;
 #[cfg(not(any(test, feature = "test-support")))]
 pub const MAX_WORKTREE_UPDATE_MAX_CHUNK_SIZE: usize = 256;
 
+#[derive(Clone, Debug)]
+pub enum WorktreeRelatedMessage {
+    UpdateWorktree(UpdateWorktree),
+    UpdateRepository(UpdateRepository),
+    RemoveRepository(RemoveRepository),
+}
+
+impl From<UpdateWorktree> for WorktreeRelatedMessage {
+    fn from(value: UpdateWorktree) -> Self {
+        Self::UpdateWorktree(value)
+    }
+}
+
+impl From<UpdateRepository> for WorktreeRelatedMessage {
+    fn from(value: UpdateRepository) -> Self {
+        Self::UpdateRepository(value)
+    }
+}
+
+impl From<RemoveRepository> for WorktreeRelatedMessage {
+    fn from(value: RemoveRepository) -> Self {
+        Self::RemoveRepository(value)
+    }
+}
+
 pub fn split_worktree_update(mut message: UpdateWorktree) -> impl Iterator<Item = UpdateWorktree> {
     let mut done = false;
 
@@ -817,7 +848,6 @@ pub fn split_worktree_update(mut message: UpdateWorktree) -> impl Iterator<Item
 
             updated_repositories.push(RepositoryEntry {
                 work_directory_id: repo.work_directory_id,
-                branch: repo.branch.clone(),
                 branch_summary: repo.branch_summary.clone(),
                 updated_statuses: repo
                     .updated_statuses
@@ -863,6 +893,47 @@ pub fn split_worktree_update(mut message: UpdateWorktree) -> impl Iterator<Item
     })
 }
 
+pub fn split_repository_update(
+    mut update: UpdateRepository,
+) -> impl Iterator<Item = UpdateRepository> {
+    let mut updated_statuses_iter = mem::take(&mut update.updated_statuses).into_iter().fuse();
+    let mut removed_statuses_iter = mem::take(&mut update.removed_statuses).into_iter().fuse();
+    let mut is_first = true;
+    std::iter::from_fn(move || {
+        let updated_statuses = updated_statuses_iter
+            .by_ref()
+            .take(MAX_WORKTREE_UPDATE_MAX_CHUNK_SIZE)
+            .collect::<Vec<_>>();
+        let removed_statuses = removed_statuses_iter
+            .by_ref()
+            .take(MAX_WORKTREE_UPDATE_MAX_CHUNK_SIZE)
+            .collect::<Vec<_>>();
+        if updated_statuses.is_empty() && removed_statuses.is_empty() && !is_first {
+            return None;
+        }
+        is_first = false;
+        Some(UpdateRepository {
+            updated_statuses,
+            removed_statuses,
+            ..update.clone()
+        })
+    })
+}
+
+pub fn split_worktree_related_message(
+    message: WorktreeRelatedMessage,
+) -> Box<dyn Iterator<Item = WorktreeRelatedMessage> + Send> {
+    match message {
+        WorktreeRelatedMessage::UpdateWorktree(message) => {
+            Box::new(split_worktree_update(message).map(WorktreeRelatedMessage::UpdateWorktree))
+        }
+        WorktreeRelatedMessage::UpdateRepository(message) => {
+            Box::new(split_repository_update(message).map(WorktreeRelatedMessage::UpdateRepository))
+        }
+        WorktreeRelatedMessage::RemoveRepository(update) => Box::new([update.into()].into_iter()),
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;