git: Avoid unnecessary git repo rescans when unrelated git files change (#59318)

# Objective

Zed triggers many git rescans whenever an outside git command modifies
files inside `.git` dir. This becomes especially problematic when
working on large repos or doing remote development on machines with slow
filesystems.

## Solution

Events for object writes, hook files, lock files, and the reflogs of
HEAD/branches/remote-tracking branches carry no git changes that Zed
cares about beyond what the ref or events already cover. So changes to
these files shouldn't trigger a full git rescan.

## Testing

I extended the existing unittests to add the additionally ignored
directories and lock files.
I also manually verified the changes by viewing the zed git debug logs
that get generated when running `git gc` on a freshly gc'ed repo.
Previously Zed triggered **7 worktree updates**, with these changes it
was reduced to **a single worktree update** which is due to
`.git/packed-refs` which we can't ignore.

**main:**

```
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] fetched remotes
2026-06-13T13:56:52+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] load merge details
2026-06-13T13:56:52+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }

2026-06-13T13:56:53+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] fetched remotes
2026-06-13T13:56:53+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] load merge details
2026-06-13T13:56:53+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }

2026-06-13T13:56:54+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-13T13:56:54+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-13T13:56:54+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-13T13:56:54+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched remotes
2026-06-13T13:56:55+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] load merge details
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }

2026-06-13T13:56:55+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched remotes
2026-06-13T13:56:55+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] load merge details
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }

2026-06-13T13:56:55+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched remotes
2026-06-13T13:56:55+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] load merge details
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }

2026-06-13T13:56:55+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched remotes
2026-06-13T13:56:55+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] load merge details
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }

2026-06-13T13:56:55+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-13T13:56:55+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-13T13:56:56+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-13T13:56:56+01:00 DEBUG [project::git_store] fetched remotes
2026-06-13T13:56:56+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-13T13:56:56+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-13T13:56:56+01:00 DEBUG [project::git_store] load merge details
2026-06-13T13:56:56+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }
```

**This PR:**

```
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] received worktree update for repositories: [UpdatedGitRepository { work_directory_id: ProjectEntryId(0), old_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), new_work_directory_abs_path: Some("/Users/lgeiger/code/zed"), dot_git_abs_path: Some("/Users/lgeiger/code/zed/.git"), repository_dir_abs_path: Some("/Users/lgeiger/code/zed/.git"), common_dir_abs_path: Some("/Users/lgeiger/code/zed/.git") }]
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] local worktree repos changed
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] run scheduled git status scan
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] starting compute snapshot
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] fetched branches, head commit, worktrees
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] fetched remotes
2026-06-15T01:19:51+01:00 DEBUG [git::repository] Checking for git status in [""]
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] fetched statuses, diff stats, stash entries
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] load merge details
2026-06-15T01:19:51+01:00 DEBUG [project::git_store] new merge details: MergeDetails { merge_heads_by_conflicted_path: {}, message: None }```


## Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed's UI standards ([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist) and [icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md) guidelines)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- Reduced number of git operations when repository state changes outside of zed

crates/git/src/git.rs

@@ -20,8 +20,19 @@ pub const DOT_GIT: &str = ".git";
 pub const GITIGNORE: &str = ".gitignore";
 pub const FSMONITOR_DAEMON: &str = "fsmonitor--daemon";
 pub const LFS_DIR: &str = "lfs";
+pub const OBJECTS_DIR: &str = "objects";
+pub const HOOKS_DIR: &str = "hooks";
+pub const LOGS_DIR: &str = "logs";
+pub const LOGS_REF_STASH: &str = "logs/refs/stash";
+pub const REBASE_MERGE_DIR: &str = "rebase-merge";
+pub const REBASE_APPLY_DIR: &str = "rebase-apply";
+pub const SEQUENCER_DIR: &str = "sequencer";
 pub const COMMIT_MESSAGE: &str = "COMMIT_EDITMSG";
-pub const INDEX_LOCK: &str = "index.lock";
+pub const FETCH_HEAD: &str = "FETCH_HEAD";
+pub const ORIG_HEAD: &str = "ORIG_HEAD";
+pub const BISECT_LOG: &str = "BISECT_LOG";
+pub const GC_PID: &str = "gc.pid";
+pub const INFO_DIR: &str = "info";
 pub const REPO_EXCLUDE: &str = "info/exclude";
 
 actions!(