Use `command` (POSIX) and `^` (Nushell) to prevent recursive function
calls when `cfg.shellWrapperName` is set to "yazi".
Previously, if `cfg.shellWrapperName` was set to "yazi", the invocation
of `yazi` within the shell integration function triggered the function
itself instead of the binary. This name conflict prevents users from
using the binary name as-is when shell integration is enabled.
Hence, fix this by using shell-specific mechanisms to target the
underlying executable, bypassing any name collisions.
This aligns with the official documentation:
- 2c839b37c8/docs/quick-start.md (L29)
- 2c839b37c8/docs/quick-start.md (L56)
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