gh-152233: Make the curses cell API work without ncursesw (ПР-152466)

gh-152233: Make the curses cell API work without ncursesw (ПР-152466)

Back complexchar, complexstr and the cell read methods (in_wch,
in_wchstr, in_wstr, getbkgrnd) with a chtype instead of a cchar_t when
ncursesw is absent, so the same code works on both builds.  A narrow
build is limited to one character per cell, encodable as a single byte in
the window's encoding (8-bit locales), with the color pair limited to the
color_pair() range.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>