New programStatus terminal capability, detected with OSC 7501

What

Claude Code now checks whether your terminal supports a new "program status" feature. It does this with an OSC sequence, a special escape code a program sends to the terminal to ask or set something.

• A new code, PROGRAM_STATUS: 7501, sits beside the existing TAB_STATUS code.
• The probe sends PROGRAM_STATUS with ? and accepts a reply whose data starts with ?. No reply means the terminal does not support it.
• The list of terminal capabilities gains programStatus, which starts as false, next to kittyKeyboard, kittyGraphics and mousePixels.
• Screen code reads the result, and one piece of text is added when it is supported. What gets shown was not traced.
• When Claude Code restores the terminal's modes (for example after being suspended and resumed), it now also sends a programStatus sequence if the feature is supported.
• A new programStatus entry records why writes to the terminal tab are not settled yet: env: CLAUDE_CODE_DISABLE_TERMINAL_TITLE, bg worker or not asked yet.

Why

The feature only works in terminals that answer the probe; others behave as before. Setting CLAUDE_CODE_DISABLE_TERMINAL_TITLE is one of the reasons Claude Code holds back these terminal tab writes.