Follow-up to: https://github.com/zed-industries/zed/pull/32637
When Zed is installed in a path containing spaces (e.g.,
`/Applications/Zed Nightly.app/Contents/MacOS/zed`), environment
variable loading fails and leaves this in the Zed log:
```
login shell exited with exit status: 127. stdout: "", stderr: "Nightly.app/Contents/MacOS/zed --printenv >&0: /Applications/Zed: No such file or directory"
```
This was not part a release (only broke in nightly), but fixes it the
issue in any case when the path to the Zed.app bundle has a space (e.g.
"Zed Nightly.app")
Release Notes:
- N/A
Fixes#11647Fixes#13888Fixes#18771Fixes#19779Fixes#22437Fixes#23649Fixes#24200Fixes#27601
Zed’s current method of loading environment variables from the login
shell has two issues:
1. Some shells—fish in particular—write specific escape characters to
`stdout` right before they exit. When this happens, the tail end of the
last environment variable printed by `/usr/bin/env` becomes corrupted.
2. If a multi-line value contains an equals sign, that line is
mis-parsed as a separate name-value pair.
This PR addresses those problems by:
1. Redirecting the shell command's `stdout` directly to a temporary
file, eliminating any side effects caused by the shell itself.
2. Replacing `/usr/bin/env` with `sh -c 'export -p'`, which removes
ambiguity when handling multi-line values.
Additional changes:
- Correctly set the arguments used to launch a login shell under `csh`
or `tcsh`.
- Deduplicate code by sharing the implementation that loads environment
variables on first run with the logic that reloads them for a project.
Release Notes:
- N/A
