TPG.UI.BuildFonts

(Re)create every named HUD/menu font at the current screen scale. Recomputes TPG.UI.scale from the screen height first, then rebuilds every entry in the local FONTS table via surface.CreateFont, and records each one's cap-centring correction into TPG.UI.CapMid (see TPG.UI.TextInBox) keyed by the SAME font name, so a caller that only has the font name string can still look up its correction. Runs once at load and again on OnScreenSizeChanged, so a font name is valid to use in surface.SetFont immediately after either of those, but NOT before the first run has happened.