feat(storage): support configurable install root

Add a LuCI install-root input, persist the selected path in UCI,
and route install, status, backup, uninstall, and runtime scripts
through the configured storage root for new installs.

Reference: custom install root flow

root/usr/libexec/openclaw-paths.sh

@@ -0,0 +1,78 @@
+#!/bin/sh
+# Shared OpenClaw install-root and derived-path helpers.
+
+OPENCLAW_DEFAULT_INSTALL_ROOT="${OPENCLAW_DEFAULT_INSTALL_ROOT:-/opt}"
+
+oc_normalize_install_root() {
+	local path="$1"
+
+	if [ -z "$path" ]; then
+		path="$OPENCLAW_DEFAULT_INSTALL_ROOT"
+	fi
+
+	case "$path" in
+		/*) ;;
+		*) path="$OPENCLAW_DEFAULT_INSTALL_ROOT" ;;
+	esac
+
+	while [ "$path" != "/" ] && [ "${path%/}" != "$path" ]; do
+		path="${path%/}"
+	done
+
+	[ -n "$path" ] || path="/"
+	printf '%s\n' "$path"
+}
+
+oc_read_install_root_from_uci() {
+	if command -v uci >/dev/null 2>&1; then
+		uci -q get openclaw.main.install_root 2>/dev/null
+	fi
+}
+
+oc_load_paths() {
+	local requested_root="$1"
+	local install_root="$requested_root"
+
+	[ -n "$install_root" ] || install_root="${OPENCLAW_INSTALL_ROOT:-}"
+	[ -n "$install_root" ] || install_root="$(oc_read_install_root_from_uci)"
+
+	OPENCLAW_INSTALL_ROOT="$(oc_normalize_install_root "$install_root")"
+	if [ "$OPENCLAW_INSTALL_ROOT" = "/" ]; then
+		OC_ROOT="/openclaw"
+	else
+		OC_ROOT="${OPENCLAW_INSTALL_ROOT}/openclaw"
+	fi
+
+	NODE_BASE="${OC_ROOT}/node"
+	OC_GLOBAL="${OC_ROOT}/global"
+	OC_DATA="${OC_ROOT}/data"
+
+	export OPENCLAW_INSTALL_ROOT OC_ROOT NODE_BASE OC_GLOBAL OC_DATA
+}
+
+oc_find_existing_path() {
+	local path
+	path="$(oc_normalize_install_root "$1")"
+
+	while [ "$path" != "/" ] && [ ! -e "$path" ]; do
+		path="${path%/*}"
+		[ -n "$path" ] || path="/"
+	done
+
+	printf '%s\n' "$path"
+}
+
+oc_install_root_uses_opt_workaround() {
+	[ "$(oc_normalize_install_root "${1:-$OPENCLAW_INSTALL_ROOT}")" = "/opt" ]
+}
+
+oc_print_env() {
+	oc_load_paths "$1"
+	cat <<EOF
+OPENCLAW_INSTALL_ROOT=$OPENCLAW_INSTALL_ROOT
+OC_ROOT=$OC_ROOT
+NODE_BASE=$NODE_BASE
+OC_GLOBAL=$OC_GLOBAL
+OC_DATA=$OC_DATA
+EOF
+}