Improve TSF integration

[o-sdn-o]

Changes:

• Improve TSF integration.
• Fix mouse wheel scrolling.
• Fix inverted text underlining.
• Assign Ctrl+Wheel to zoom cells and CapsLock+0 to reset zoom in GUI mode. https://github.com/directvt/vtm/issues/571#issuecomment-2260418861
• Fix Win key sticking (after Win+Space).
• Fix emoji input on Windows 8.
• Built-in terminal:
  • Fix color text copying to clipboard.
  • Fix Enter key in WSL (0x0A->0x0D).
• Change settings structure in settings.xml:
  • Alternate scroll mode: <altscroll enabled="yes" step=1/> -> <altscroll="on"/>.
  • Drop config parameter <config/appearance/defaults/wheel_dt=3 /> <!-- Mouse scrolling wheel step. --> in favor of system-wise mouse settings (aka lines to scroll setting).
• Change dtvt protocol (incompatibility with previous vtm versions).