feat(cli): run commands in bottom split pane instead of new window

dot_local/bin/executable_pj-palette

@@ -10,9 +10,9 @@
 #   pj-palette --cmd ROOT CMD…
 #                            run a quick-action command in ROOT
 #
-# Every item opens a new tmux window in the project root. The command runs in
-# the foreground; when it exits the window keeps a shell (with the output
-# above it) instead of closing.
+# Every item opens a full-width split along the bottom of the window (25% of
+# its height) in the project root. The command runs in the foreground; when it
+# exits the pane keeps a shell (with the output above it) instead of closing.
 
 set -uo pipefail
 self=$(readlink -f "$0")
@@ -56,15 +56,15 @@ icon_for() {
     esac
 }
 
-# tmux action that opens a new window in DIR running ARGV directly (no shell,
-# so nothing is re-parsed by fish). The palette wrapper evals the string in
-# bash, hence %q.
-window_action() {
+# tmux action that opens a full-width bottom split (25%) in DIR running ARGV
+# directly (no shell, so nothing is re-parsed by fish). The palette wrapper
+# evals the string in bash, hence %q.
+split_action() {
     local dir=$1
     shift
     local q
     q=$(printf '%q ' "$@")
-    printf 'new-window -c %q %s' "$dir" "$q"
+    printf 'split-window -v -f -l 25%% -c %q %s' "$dir" "$q"
 }
 
 items=()
@@ -76,7 +76,7 @@ item() { # category icon title description aliases(csv) tmux-action
 quick() { # icon title aliases dir argv…
     local icon=$1 title=$2 aliases=$3 dir=$4
     shift 4
-    item Quick "$icon" "$title" "in ${dir/#$HOME/~}" "$aliases" "$(window_action "$dir" "$self" --cmd "$dir" "$@")"
+    item Quick "$icon" "$title" "in ${dir/#$HOME/~}" "$aliases" "$(split_action "$dir" "$self" --cmd "$dir" "$@")"
 }
 
 # ── Quick actions, from the files at the project root ─────────────────────
@@ -114,7 +114,7 @@ while IFS=$'\t' read -r display kind target troot runner _file; do
     desc="$runner $target"
     [ "$troot" != "$root" ] && desc+="  (${troot#"$root"/})"
     item "Tasks: $tag" "$(icon_for "$tag")" "$target" "$desc" "" \
-        "$(window_action "$troot" "$self" --run "$kind" "$target" "$troot" "$runner")"
+        "$(split_action "$troot" "$self" --run "$kind" "$target" "$troot" "$runner")"
 done < <(PJ_QUIET=1 pj --list 2>/dev/null)
 
 if [ ${#items[@]} -eq 0 ]; then