Scintilla 5.5.8 Upstream Cherry-Pick Patches

All beneficial changes from Scintilla 5.5.8 have been applied to NP3's 5.5.7 baseline.

✅ All Changes Applied

Patch	Description	Files Modified
`001_undo_selection_redraw.patch`	Fix selection drawing after undo	`Editor.cxx`
`002_listbox_opaque_colors.patch`	Force autocomplete colors opaque	Already in NP3
`003_listbox_bitmap_sizing.patch`	Fix bitmap sizing (no blank bg)	Already in NP3
`004_unicode16_update.md`	Unicode 16 character categories	`CharacterCategoryMap.cxx`
`005_ptrdiff_alias.md`	PTRDIFF_DOESNT_ALIAS_INT option	`RunStyles.cxx`
`006_selection_serialization_format.patch`	New serialization format	`Selection.cxx`, `Selection.h`
`007_rectangular_indent_fix.patch`	Rectangular selection indent	`Editor.cxx`

File	Change
`CallTip.cxx`	Removed macOS-specific default colors
`CaseConvert.cxx`	Unicode 16 case folding table updates
`CellBuffer.cxx`	`is_convertible_v` type check + `type_traits` include
`EditView.cxx`	Bidi data bounds check fix
`Editor.cxx`	`SetSelectionFromSerialized` uses `Redraw()` instead of `InvalidateStyleRedraw()`

[!NOTE] PositionCache.cxx/h was NOT updated - has noexcept specification changes that conflict with NP3's base class declarations.

These files have NP3 patches and retain their customizations:

win32/PlatWin.cxx - 4-parameter AdjustWindowRectForDpi
win32/ScintillaWin.cxx - DPI exports, popup menu control
src/Editor.cxx - Zoom methods, strike style, drag policies (with 5.5.8 fixes merged in)

Build completed successfully with exit code 0:

Notepad3.vcxproj -> R:\GitHub\Notepad3\Bin\Release_x64_v145\Notepad3.exe