Add the ability to name/re-name a window

[jcollie]

Discussed in #10468

^{Originally posted by joshuaboys January 27, 2026}
I know I am finding myself running more and more windows (made up of many tabs.. regularly hitting a ghostty limit I didn't know existed) these days and it would be such a quality of life improvement to be able to rename the windows themselves.

I've looked into it from a Linux perspective and it doesn't look like a huge amount of effort. Basically we copy the existing prompt_surface_title implementation approach but at the Tab level instead of Surface level. (its an oversimplification but that is the core part)

[jcollie]

Note that we already have #9904 for renaming a tab on GTK. Once #9904 is merged it's the logical next step to add renaming for windows so that the window title stays fixed no matter what happens to the underlying tab/surface titles. Not sure about the state of macOS.

[joshuaboys]

Yep and I totally glazed over that PR which is great because that handles most of the work I thought was needed.