fix: improve shell compatibility and process cleanup

Preserve literal paths and arguments, use portable command options, validate startup configuration, and retain scripts when downloads fail.

Ensure task watchdogs and process groups are cleaned up across Bash versions, with compatibility and process lifecycle regression coverage.

shell/task.sh

@@ -1,9 +1,9 @@
 #!/usr/bin/env bash
 
 dir_shell=$QL_DIR/shell
-. $dir_shell/share.sh
-. $dir_shell/api.sh
-. $dir_shell/task-timeout.sh
+. "$dir_shell/share.sh"
+. "$dir_shell/api.sh"
+. "$dir_shell/task-timeout.sh"
 
 trap 'single_hanle SIGINT'  INT
 trap 'single_hanle SIGTERM' TERM
@@ -48,7 +48,7 @@ handle_log_path() {
   fi
 
   if [[ -z ${ID:=} ]]; then
-    ID=$(cat $list_crontab_user | grep -E "$cmd_task.* $file_param" | perl -pe "s|.*ID=(.*) $cmd_task.* $file_param\.*|\1|" | head -1 | awk -F " " '{print $1}')
+    ID=$(cat "$list_crontab_user" | grep -E "$cmd_task.* $file_param" | perl -pe "s|.*ID=(.*) $cmd_task.* $file_param\.*|\1|" | head -1 | awk -F " " '{print $1}')
   fi
   local suffix=""
   if [[ ! -z $ID ]]; then
@@ -89,10 +89,10 @@ handle_log_path() {
     log_path="$real_log_path"
   fi
 
-  cmd="2>&1 | tee -a $dir_log/$log_path"
+  printf -v cmd '2>&1 | tee -a %q' "$dir_log/$log_path"
   make_dir "$dir_log/$log_dir"
   if [[ "${no_tee:=}" == "true" ]]; then
-    cmd=">> $dir_log/$log_path 2>&1"
+    printf -v cmd '>> %q 2>&1' "$dir_log/$log_path"
   fi
 
   if [[ "${real_time:=}" == "true" ]]; then
@@ -162,5 +162,5 @@ define_program "${task_shell_params[@]}"
 handle_log_path "${task_shell_params[@]}"
 init_begin_time
 
-eval . $dir_shell/otask.sh "$cmd"
+eval '. "$dir_shell/otask.sh"' "$cmd"
 exit 0