[Bug] Welcome command uses POSIX syntax in fish panes #803

Operating system / 操作系统

Windows (WSL, Arch Linux); also affects native Unix with fish.

Pebrel version / 版本号

2.2.0; the same welcome command is present on main at 1b58f5d.

Shell in the affected pane / 出问题的面板用的 Shell

fish 4.9.3

Steps to reproduce / 复现步骤

1. Enable the new-tab welcome screen (fetch=1).
2. Open a WSL pane whose default shell is fish.

Expected behavior / 期望结果

The welcome screen runs and returns to a usable fish prompt.

Actual behavior / 实际结果

The injected welcome command remains at the prompt and does not run. It contains POSIX if ...; then ...; fi syntax, which fish rejects. The same command is used on Unix without distinguishing the interactive shell.

Verification / 验证

fish -n -c rejects the current command. An interactive fish PTY reproduces the shell syntax incompatibility; the welcome script can be executed through sh -c from fish while retaining the existing fastfetch and uname branches.