Move HISTFILE/HISTSIZE/SAVEHIST/HISTFILESIZE/HISTCONTROL into the shared
shell/exports as env vars; each shell ignores the other's name-specific
ones. Dedup that can't be an env var stays per-shell: HISTCONTROL=ignoreboth
for bash, setopt hist_ignore_all_dups/hist_ignore_space for zsh.
Also mkdir -p the HISTFILE parent in shell/interactive, so a fresh host
doesn't silently drop history when ~/.cache/shell is absent.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
daniil-berg
ad5a6c98ea
