Fix launching remote Bash with shell integration enabled

[dakra]

Problem

Starting a remote Bash shell over TRAMP with ghostel-tramp-shell-integration enabled fails at launch:

/bin/bash: --: invalid option
Usage:  /bin/bash [GNU long option] [option] ...

ghostel assembled the argv as /bin/bash -i --rcfile FILE. Bash requires all multi-character (long) options to come before any single-character options, so the long --rcfile following the short -i is rejected.

This is the same bug as #470; this PR fixes it at the source rather than with a post-hoc argument sort.

Fix

shell-args is built by appending two groups: the login/interactive defaults (-i/-l) and the integration args (bash's --rcfile/--posix, fish's -C). The fix simply swaps the append order so the integration args lead:

(shell-args (append
             integration-args
             (or extra-shell-args
                 (and remote-p
                      (ghostel--default-remote-shell-args
                       shell remote-integration)))))

For remote Bash this yields /bin/bash --rcfile FILE -i, which launches cleanly. The reorder is:

• zsh — a no-op (integration args are always nil),
• fish — harmless (no long-before-short rule; -C stays adjacent to its value),
• local bash — harmless (--posix/--login are order-independent).

User-supplied bash args are not reordered within their own list, so the long-before-short requirement is now documented in the ghostel-shell and ghostel-tramp-shells docstrings.

Verification

• make -j8 all passes (build + tests + lint).
• Verified live over TRAMP/SSH against a real remote Bash 4.4.20 host: reproduced the --: invalid option failure without the change, and confirmed a clean interactive prompt with it.