When opening a terminal in a remote project, skip local-only path
operations (home dir fallback, shell expansion, is_dir checks) so the
remote shell opens in the remote user’s home directory by default.

Closes #49613.

Before you mark this PR as ready for review, make sure that you have:
- [ ] Added a solid test coverage and/or screenshots from doing manual
testing
- [x] Done a self-review taking into account security and performance
aspects
- [x] Aligned any UI changes with the [UI
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Release Notes:

- Prevent local path resolution for remote terminals