Ports retail UIElement_Text editable one-line mode (caret = glyph index;
caret pixel-X = sum of glyph advances via UiDatFont) and ChatInterface's
100-entry command history (up/down arrow; sentinel -1 = live line).
Submit (Enter/KeypadEnter) fires OnSubmit callback, clears, pushes history.
Draws via DrawStringDat (dat font) or DrawString (BitmapFont) fallback.
AcceptsFocus=true + IsEditControl=true so UiRoot routes Char/KeyDown to it
and suppresses global hotkeys while typing. 6 new tests, all green.
Decomp refs: UIElement_Text::MoveCursor @0x468d00,
UIElement_Text::FindPixelsFromPos @0x472b40,
ChatInterface::ProcessCommand @0x4f5100
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
