Add UiChatView, a transcript widget for the retail-look UI: renders the
ChatVM tail bottom-pinned (newest at the bottom, like retail) with
mouse-wheel scrollback and whole-line vertical clipping so text stays
inside the frame. Hosted in a draggable/resizable UiNineSlicePanel and
wired into the UiHost next to the vitals window, fed by a dedicated
ChatVM (200-line tail) over the same live ChatLog. Per-ChatKind colour
palette (speech white, tells magenta, channels blue, system yellow,
emotes grey, combat orange).
This is the read-only foundation. The next sub-step adds glScissor
clipping + word-wrap, drag-to-select, and Ctrl+C copy -- the last needs
a CapturesPointerDrag opt-out on UiElement so an interior drag selects
text instead of moving the window (today an interior drag still moves
the window, same as the vitals panel).
Tests: UiChatView.ClampScroll (pin-to-bottom, cap-at-overflow,
never-negative).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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