Improve /speckit.tasks - reminder to create VSCode todo list and update tasks.md on phase completion

[kryltsov]

Would it be a good idea to change prompt for at least VSCode to:

Always add the first task in each Phase "Create VSCode todo list" as sometimes it skips it
Always add the last task into each Phase to 'Update tasks.md' with tasks completed in that phase' as sometimes it forgets to do it.