This adds the ability to change a _tab_ title. The previous
functionality was tied to a specific _surface_. A tab title will stick
to the current tab regardless of active splits and so on.
This follows the nomenclature that macOS terminal app does which is
"title vs terminal title" (although we explicitly use "tab" in various
places, I may remove that in the future).
**This is macOS only. GTK is tracked here: #9880**. I did macOS only
because thats the machine I'm on. It'll be trivial to add this to GTK,
too.
## Demo
https://github.com/user-attachments/assets/d9446785-d919-4212-8553-db50c56c8c2f
(The option is also in the main menu, the context menu, and the command
palette)
## AI Disclosure
This PR was done fully with Amp, I didn't write a single line of code at
the time of writing this PR description. I reviewed everything though
and fully understand it all. Its a mimic more or less of the prompt
surface title work (although we did unify some stuff like the apprt
action).
cba82e976c