Wait for the operator in the middle of a phase

A phase can now ask the operator for input while it runs and react to the answer, so a calibration loop no longer needs one phase per try.

• Added ui.wait() to the TofuPilot Framework: the phase blocks until the operator clicks Continue, then gets the answer with numbers, switches and multiple choices already typed. Each call shows the phase's screen again with the last answer and the values the phase set since.
• Changed Esc in the terminal UI to cancel a phase prompt on every screen: the phase ends in error instead of continuing on an empty answer, and a phase blocked in ui.wait() gets ui.WaitCancelled.
• Changed --ui-values to answer the first prompt of a phase only, so a phase that loops on ui.wait() asks the following ones.
• Updated Studio and the dashboard operator view to replace a waiting phase's previous prompt with its new one.