For the shapeshifting part, you’ll need to create a new action. There are lots of ways of organizing it, but I would start by creating a new kind of value, “form”, which can be human, wolf, or whatever.
A form is a kind of value. The forms are human and wolf.
Now the player needs to be given a form.
The player has a form. The form of the player is wolf.
(Depending on what your game is about, you might want everyone to have a form. In which case, you could write “A person has a form. The form of a person is usually human. The form of the player is wolf.”)
Next we create the shapeshifting action, and write basic rules for it.
Shapeshifting is an action applying to one form.
Check shapeshifting when the form understood is the form of the player:
say "You are already in [the form understood] form." instead.
Carry out shapeshifting:
now the form of the player is the form understood.
say "You feel the change coming over you. You now have the form of a [the form understood]."
You also need to provide verbs which let the player use the new action. (None are created by default.)
Understand "shift to [a form]" or "turn to/-- [a form]" or "become [a form]" as shapeshifting.
(The to/— makes this word optional, so “TURN HUMAN” will also work.)
Now we’re ready to set up the situation that you described:
The Bedroom is a room. Some clothes are in the bedroom. The clothes are wearable.
The Top Landing is north from the bedroom.
Check going from the bedroom:
if the form of the player is wolf:
say "No! I can't let the family know my secret!" instead;
otherwise if the clothes are not worn:
say "If you think I’m going anywhere naked, think again!" instead.
(This could be done with two separate rules, and it could be done using instead rules instead of check: mainly a matter of taste.)
No doubt you will want to write other general rules concerning such things as public nudity and shapeshifting exhibitions. So here’s a start.
Instead of taking off the clothes when the location is not the bedroom:
say "This is hardly the place, don't you think?"
Instead of shapeshifting in the presence of a person who is not the player:
say "No! I can't let anyone see."