Add curses.scr_dump(), scr_restore(), scr_init() and scr_set() #152260

The curses module can serialize a single window with window.putwin() / curses.getwin(), but it has no way to dump and restore the whole screen. The four X/Open functions that do this are still missing:

• scr_dump(filename) — write the current virtual screen to a file.
• scr_restore(filename) — set the virtual screen to a dumped file; the next doupdate()/refresh() paints it.
• scr_init(filename) — use a dump as the assumed current terminal contents (e.g. after another program drew the screen).
• scr_set(filename) — combine scr_restore() and scr_init().

These are the whole-screen counterpart of putwin()/getwin(). Unlike those (which take a Python file object, mirroring C putwin(WINDOW *, FILE *)), the C scr_* functions are filename-based (they fopen internally), so the Python wrappers take a filename — a str or a path-like object.

Proposed API:

curses.scr_dump(filename)
curses.scr_restore(filename)
curses.scr_init(filename)
curses.scr_set(filename)

Linked PRs

• gh-152260: Add curses.scr_dump(), scr_restore(), scr_init() and scr_set() #152261
• gh-152260: Fix test_scr_dump() on macOS #152340
• gh-152260: Fix flaky curses test_scr_dump on macOS #152390