feat(windows): support resizable frameless windows with native shadow

[zhuzipu]

feat(windows): support resizable frameless windows with native shadow

Enable window resizing for frameless windows when shadow=True on Windows.
Previously, setting frameless=True stripped WS_THICKFRAME and the DWM
sizing border was not available, making resizable=True ineffective when
the native shadow was enabled.

The fix follows the approach used by Electron (borderless-window):

• Subclass the window procedure to intercept WM_NCCALCSIZE and return 0,
  which removes the non-client area while keeping the DWM frame intact.
• Block WM_NCUAHDRAWCAPTION and WM_NCUAHDRAWFRAME to prevent the themed
  window border from being drawn over the client area.
• Pass -1 as lParam to WM_NCACTIVATE so DefWindowProc does not repaint
  the non-client border on activation changes.
• Handle WM_NCHITTEST using client-coordinate hit testing (SM_CXFRAME +
  SM_CXPADDEDBORDER), with diagonal corner handles wider than the sides,
  matching standard Windows behavior.
• Forward WM_NCPAINT to DefWindowProc so DWM continues to draw the
  native window shadow from the extended frame.
• Handle WM_SETCURSOR to show the appropriate sizing cursor for each
  hit-test result.
• Re-add WS_THICKFRAME to the window style so the system engages its
  resize modal loop when an edge hit-test result is returned.
• In EdgeChrome, when the form is frameless + resizable, size the
  WebView2 control to leave a thin border at the window edges so
  WM_NCHITTEST messages can reach the parent window procedure.

Thanks for TRAE WORK ( AI ) 🎉🎉🎉~