Sanctum
The room at the end of the hall still waits.
The door is not explained here. Only the quiet around it is. Encryption can be added later without making the room louder.
Encryption-ready notes
The room waits for a phrase no one else should overhear.
Keys can be derived later; the door still remembers its shape.
Something private can live here without explaining itself.
If the lock opens, it should do so quietly.
Sanctum is reserved for content that should not live in the open archive. The UI is in place now so that encryption and access control can be connected without reworking the layout.