Like the other tabs, except that the screen keeps what the page edits that
isn't a config setting (the compatibility reports flag, which is written
back when the screen closes, and the Windows memstick checkboxes' state) in
a SystemPageState it passes in. The page's handlers move with it, as
functions taking the page host or that state.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Only moves code. The tabs other than System were built by static functions
in GameSettingsScreen.cpp, in place of the old methods, to keep the previous
change's diff readable. Now each tab has its own file, with just the
includes it needs, and MainSettingsPages.h declares their builders.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
