Feature request: set terminal window title using OSC escape sequences

tig does not set the terminal window title. This makes it difficult to distinguish between multiple tig instances when using a window manager, a window switcher, or a taskbar that relies on the window title.

Most modern TUI applications (vim, htop, etc.) set the terminal window title via OSC escape sequences to identify themselves. tig should do the same.

A reasonable default title could follow a format like tig (<repo>): <view> (e.g. tig (linux): main), updating dynamically as the user switches views.

The implementation would involve:

• Writing OSC 0 sequences (ESC ] 0 ; <title> BEL) directly to the tty
• Saving and restoring the previous title on startup/exit using the xterm title stack (CSI 22;2 t / CSI 23;2 t)

These sequences are supported by most modern terminal emulators and silently ignored by those that do not support them.