Expose the user menu as a `types.lines` option instead of a baked source
file. The shipped menu is a `mkBefore` definition (not a `default`, which a
consumer definition would drop), so `local.mc.menu = "…"` appends entries
after the baseline and `lib.mkForce "…"` replaces it wholesale.
`ini` stays a baked source file: it is section/key=value, so append-to-extend
risks duplicate keys — not a safe override path.
Public baseline module: installs `mc` plus `ouch` (backs the F2 pack/unpack
entries, archive format inferred from the extension), and ships `ini`, `menu`,
and a generated `panels.ini` into `$XDG_CONFIG_HOME/mc`.
`local.mc.otherDir` exposes the other-panel start dir as an option defaulting
to `config.home.homeDirectory`, so the one personal value isn't baked in. The
F2 user menu is trimmed to the entries that match this config (imv/zathura/mpv
openers, ouch pack/unpack, man view); the stock rcp/uudecode/news/latex cruft
is dropped. `auto_save_setup=false` keeps mc from rewriting the read-only store
symlinks on exit.
daniil-berg
