Fixes#42945
## Problem
When opening a single file via command line (e.g., `zed
~/Downloads/file.txt`), the terminal panel was opening in the root
directory (/) instead of the file's directory.
## Root Cause
The code only checked for active project directory, which returns None
when a single file is opened. Additionally, file worktrees weren't
handling parent directory lookup.
## Solution
Added fallback logic to use the first project directory when there's no
active entry, and made file worktrees return their parent directory
instead of None.
## Testing
- All existing tests pass
- Added test coverage for file worktree scenarios
- Manually tested with `zed ~/Downloads/file.txt` - terminal now opens
in correct directory
This improves the user experience for users who frequently open single
files from the command line.
## Release Notes
- Fixed terminal opening in root directory when editing single files
from the command line
Engin Açıkgöz
f17d2c92b6