Hi,

Since emacs-29 the Eshell has been enhanced for the ansi-color a lot.
And the function `eshell-exec-visual` can support the executables with
colors, eg VIM, tmux...
I have tested the "/bin/ls --color=tty", "/bin/grep --color=tty" ...
and other executables in Eshell with "export TERM=eshell-color", they
all work great.

So we can safely export eshell's "TERM" with `eshell-term-name` to
support executables with colors.
I attached the patch, please help review it. Thanks.