UiChannelMenu → UiMenu: removed ChatChannelKind, the 14-item array, the
button-text map, and the availability default. Generic surface: MenuItem
(label + object? Payload), Selected (object?), OnSelect, EnabledProvider,
ButtonLabelProvider, RowsPerColumn/RowHeight/ColumnWidth (all settable).
All draw/event mechanics unchanged — same popup geometry, same click
coordinates, same 8-piece bevel, same 3-slice button face.
ChatWindowController gains ChannelItems[], ChannelButtonLabel(), and
ChannelAvailable() (verbatim from old widget), and populates the
factory-built Type-6 UiMenu via find-by-id rather than constructing a
replacement widget. The Menu property type is now UiMenu. OnChannelChanged
wrap replaced with the generic OnSelect wrap for the ReflowInputRow hook.
DatWidgetFactory registers Type 6 → new UiMenu().
Tests: UiChannelMenuTests → UiMenuTests (10 tests, all green); factory
Type6 test added; ChatWindowControllerTests updated to use OnSelect.
Divergence register: AP-42 added (flat item model vs retail nested-submenu
MakePopup @0x46d310 — latent, unreachable through the chat menu).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>