fix(gui): scale main-toolbar icons on hi-DPI displays - #294

The preferences dialog's page list (General, Connection, Directories,
etc.) fed 16x16 bitmaps into a fixed-size wxImageList, so on
DPI-aware builds the icons render at 16 physical pixels — tiny and
blurry on hi-DPI screens, same problem as the main toolbar (#294).

Hand the icons to the list control as wxBitmapBundles instead
(wxListCtrl::SetSmallImages, wx >= 3.2), each built from the 16px art
plus a wxIMAGE_QUALITY_HIGH 2x upscale with the mask converted to an
alpha channel first. The macOS-only right/bottom padding is applied
per resolution so the padded canvas keeps its proportions at 2x.

Co-authored-by: Carlos Barrero <[email protected]>
Co-authored-by: Claude Fable 5 <[email protected]>

* fix(gui): scale main-toolbar icons on hi-DPI displays

The toolbar icons (Downloads, Shared Files, etc.) were stored in a
fixed 32x32 wxImageList and handed to wxToolBar as plain wxBitmaps.
Since the executable declares PerMonitorV2 DPI awareness (amule-org#780), those
bitmaps are drawn at 32 *physical* pixels, so on 4K / scaled displays
the icons render tiny and blurry while the rest of the UI scales.

Store each toolbar icon as a wxBitmapBundle instead (wx >= 3.2),
built from the original 32px art plus a wxIMAGE_QUALITY_HIGH 2x
upscale, converting the transparency mask to an alpha channel first
so the scaler doesn't smear the mask colour into the icon edges.
Drop the hard-coded SetToolBitmapSize(32,32) so the toolbar derives
the logical size from the bundles and scales it per monitor DPI.

SetMessagesTool gains a bounds guard because m_CurrentBlinkBitmap
starts as a stale sentinel (24) that the old wxImageList::GetBitmap
tolerated but vector indexing must not.

Co-Authored-By: Claude Fable 5 <[email protected]>

* refactor(gui): name toolbar icon indexes and drop dead code after review

Code-review follow-ups to the wxBitmapBundle toolbar change:

- Add ToolbarSkinEnum (mirroring ClientSkinEnum) so the m_tblist
  indexes duplicated across Apply_Toolbar_Skin, ShowConnectionState,
  OnGUITimer and the constructor are named instead of magic numbers
  whose meaning depends on the Add_Skin_Icon call order.
- Initialize m_CurrentBlinkBitmap to Toolbar_Messages instead of the
  stale sentinel 24 (a fossil amuleDlgImages() resource id, never a
  valid m_tblist index) and drop the SetMessagesTool bounds guard that
  existed only to defend against it; both callers assign a valid index
  right before calling, so behavior is identical.
- Remove the #ifdef __WXCOCOA__ branches in ShowConnectionState and
  SetMessagesTool: the old wxCocoa port was removed from wxWidgets
  before the 3.2 minimum this project requires (modern macOS defines
  __WXOSX_COCOA__), so those lines could never compile again.
- Use the two-bitmap wxBitmapBundle::FromBitmaps overload instead of
  building a wxVector by hand.

Co-Authored-By: Claude Fable 5 <[email protected]>

* style(gui): use emplace_back for the fallback toolbar bundle

Fixes the clang-tidy Tier-2 modernize-use-emplace warning on the
wxBitmapBundle fallback path in Add_Skin_Icon.

Co-Authored-By: Claude Fable 5 <[email protected]>

---------

Co-authored-by: Carlos Barrero <[email protected]>
Co-authored-by: Claude Fable 5 <[email protected]>

)

The preferences dialog's page list (General, Connection, Directories,
etc.) fed 16x16 bitmaps into a fixed-size wxImageList, so on
DPI-aware builds the icons render at 16 physical pixels — tiny and
blurry on hi-DPI screens, same problem as the main toolbar (amule-org#294).

Hand the icons to the list control as wxBitmapBundles instead
(wxListCtrl::SetSmallImages, wx >= 3.2), each built from the 16px art
plus a wxIMAGE_QUALITY_HIGH 2x upscale with the mask converted to an
alpha channel first. The macOS-only right/bottom padding is applied
per resolution so the padded canvas keeps its proportions at 2x.

Co-authored-by: Carlos Barrero <[email protected]>
Co-authored-by: Claude Fable 5 <[email protected]>