Represent git statuses more faithfully (#23082)

First, parse the output of `git status --porcelain=v1` into a
representation that can handle the full "grammar" and doesn't lose
information.

Second, as part of pushing this throughout the codebase, expand the use
of the existing `GitSummary` type to all the places where status
propagation is in play (i.e., anywhere we're dealing with a mix of files
and directories), and get rid of the previous `GitSummary ->
GitFileStatus` conversion.

- [x] Synchronize new representation over collab
  - [x] Update zed.proto
  - [x] Update DB models
- [x] Update `GitSummary` and summarization for the new `FileStatus`
- [x] Fix all tests
  - [x] worktree
  - [x] collab
- [x] Clean up `FILE_*` constants
- [x] New collab tests to exercise syncing of complex statuses
- [x] Run it locally and make sure it looks good

Release Notes:

- N/A

---------

Co-authored-by: Mikayla <mikayla@zed.dev>
Co-authored-by: Conrad <conrad@zed.dev>

crates/collab/src/db/queries/projects.rs

@@ -360,6 +360,8 @@ impl Database {
                         update.updated_repositories.iter().flat_map(
                             |repository: &proto::RepositoryEntry| {
                                 repository.updated_statuses.iter().map(|status_entry| {
+                                    let (repo_path, status_kind, first_status, second_status) =
+                                        proto_status_to_db(status_entry.clone());
                                     worktree_repository_statuses::ActiveModel {
                                         project_id: ActiveValue::set(project_id),
                                         worktree_id: ActiveValue::set(worktree_id),
@@ -368,8 +370,11 @@ impl Database {
                                         ),
                                         scan_id: ActiveValue::set(update.scan_id as i64),
                                         is_deleted: ActiveValue::set(false),
-                                        repo_path: ActiveValue::set(status_entry.repo_path.clone()),
-                                        status: ActiveValue::set(status_entry.status as i64),
+                                        repo_path: ActiveValue::set(repo_path),
+                                        status: ActiveValue::set(0),
+                                        status_kind: ActiveValue::set(status_kind),
+                                        first_status: ActiveValue::set(first_status),
+                                        second_status: ActiveValue::set(second_status),
                                     }
                                 })
                             },
@@ -384,7 +389,9 @@ impl Database {
                         ])
                         .update_columns([
                             worktree_repository_statuses::Column::ScanId,
-                            worktree_repository_statuses::Column::Status,
+                            worktree_repository_statuses::Column::StatusKind,
+                            worktree_repository_statuses::Column::FirstStatus,
+                            worktree_repository_statuses::Column::SecondStatus,
                         ])
                         .to_owned(),
                     )
@@ -759,10 +766,7 @@ impl Database {
                     let mut updated_statuses = Vec::new();
                     while let Some(status_entry) = repository_statuses.next().await {
                         let status_entry: worktree_repository_statuses::Model = status_entry?;
-                        updated_statuses.push(proto::StatusEntry {
-                            repo_path: status_entry.repo_path,
-                            status: status_entry.status as i32,
-                        });
+                        updated_statuses.push(db_status_to_proto(status_entry)?);
                     }
 
                     worktree.repository_entries.insert(