fix(ui): vendor dropdown polish — authored arrow-cap with open/closed flip, downward popup, left-aligned rows

Three gate findings, each settled by authored data rather than
invention: the button face is retail's two-piece assembly and the
17x19 arrow-cap 0x1000034E now renders with its authored
Normal(closed)/Highlight(open) states; the popup direction is an
AUTHORED attribute (UIElement_Menu::Open pc:120210-120252 — bool
attr 5, chat authors upward=true, the vendor menu authors nothing and
defaults downward), so both menus are now byte-faithful with no
special case; and the 19/20px text indents were chat-specific
checkbox/LED clearances the vendor rows don't author — measured
against the live retail font, "Spell Components" overflowed by 11px
and now fits with 8px to spare. Chat's menu defaults are bit-identical
and its tests untouched.

AP-161's arrow-cap note closes. #351 files the pre-existing FarLoad
Debug flake (three sightings today, never in clean-room Release).

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

tests/AcDream.App.Tests/UI/UiMenuTests.cs

@@ -363,4 +363,130 @@ public class UiMenuTests
         Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, RawX(10), ly)));
         Assert.NotNull(fired);   // popup was still open -> the click landed on a real row
     }
+
+    // ── Vendor dropdown polish (items 1-3): arrow indicator, popup direction,
+    // left alignment. See VendorUiController's "G6"/"G7"/"G8" class-doc
+    // paragraphs for the retail citations these three fixes are ported from.
+
+    [Fact]
+    public void ArrowCapSprite_FlipsBetweenClosedAndOpen_OnToggle()
+    {
+        // G6: UiMenu.CurrentArrowCapSprite projects _open onto the two
+        // configured sprites — the same selection DrawArrowCap makes every
+        // frame, exposed as a test seam since the class has no OnDraw harness.
+        var menu = new UiMenu
+        {
+            Width = 80f, Height = 18f,
+            Items = ChannelItems,
+            ArrowCapClosedSprite = 111u,
+            ArrowCapOpenSprite = 222u,
+        };
+
+        Assert.Equal(111u, menu.CurrentArrowCapSprite);   // closed by default
+
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, 5)));   // open
+        Assert.Equal(222u, menu.CurrentArrowCapSprite);
+
+        // A click in the popup's bevel ring (below every real row, iy >= InteriorH)
+        // closes without picking anything — the arrow must flip straight back.
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, -1)));
+        Assert.Equal(111u, menu.CurrentArrowCapSprite);
+    }
+
+    [Fact]
+    public void ArrowCapSprite_DefaultsToZero_NoOpForMenusThatDontAuthorOne()
+    {
+        // Chat's own controller never sets ArrowCapClosedSprite/OpenSprite (its
+        // arrow is baked into NormalSprite/PressedSprite already) — confirm the
+        // class default stays a no-op id so DrawArrowCap's `id == 0` guard fires.
+        var menu = new UiMenu();
+        Assert.Equal(0u, menu.CurrentArrowCapSprite);
+        Assert.Equal(0u, menu.ArrowCapClosedSprite);
+        Assert.Equal(0u, menu.ArrowCapOpenSprite);
+    }
+
+    [Fact]
+    public void OpenUpward_DefaultsTrue_PreservingChatsExistingUpwardGeometry()
+    {
+        // Every test above (chat's own shape) relies on this default never
+        // changing — G7 added the property but must not move chat's popup.
+        Assert.True(new UiMenu().OpenUpward);
+    }
+
+    [Fact]
+    public void OpenUpward_False_MovesThePopupBelowTheButton_NotAbove()
+    {
+        var menu = new UiMenu
+        {
+            Width = 80f, Height = 18f,
+            Items = ChannelItems,
+            Selected = (object?)ChatChannelKind.Say,
+            EnabledProvider = ChannelAvailable,
+            OpenUpward = false,
+        };
+
+        object? fired = null;
+        menu.OnSelect = p => fired = p;
+
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, 5)));   // open
+
+        // Where "Chat to All" (index 2, Say) used to resolve when the popup
+        // opened UPWARD (see Select_AvailableLeftColumnItem_FiresOnSelect,
+        // ly=-76) is now empty space above the button. With OpenUpward=false
+        // this ly no longer satisfies "clicked in popup" at all, so UiMenu
+        // treats it as an ordinary button click and just re-closes the menu —
+        // it must NOT fire a selection.
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, -76)));
+        Assert.Null(fired);
+
+        // Re-open and click the SAME row (index 2, "Chat to All"/Say) at its
+        // NEW, downward position: the popup's top is now at the button's own
+        // bottom edge (ly = Height), not -OuterH.
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, 5)));   // open
+        const int border = 5; // RetailChromeSprites.Border
+        float iy = 2 * menu.RowHeight + menu.RowHeight / 2f;
+        int ly = (int)(menu.Height + iy + border);
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, ly)));
+        Assert.Equal(ChatChannelKind.Say, fired);
+    }
+
+    [Fact]
+    public void OpenUpward_False_HitTestCoversTheButtonAndTheDownwardPopup()
+    {
+        var menu = new UiMenu { Width = 80f, Height = 18f, Items = ChannelItems, OpenUpward = false };
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, 5)));   // open
+
+        // Public surface only exposes hit-testing via the protected OnHitTest,
+        // so exercise it the same indirect way the rest of this file does:
+        // a MouseDown at a point inside the downward popup's bevel is accepted
+        // as "in popup" (closes without firing), proving the popup geometry
+        // itself now lives below Height rather than above 0.
+        float outerH = menu.RowsPerColumn * menu.RowHeight + 2 * 5;
+        int belowPopupBottom = (int)(menu.Height + outerH) + 1;   // just past the popup's own bottom edge
+        // Outside the popup entirely -> falls through to the button-toggle path.
+        object? fired = null;
+        menu.OnSelect = p => fired = p;
+        Assert.True(menu.OnEvent(new UiEvent(0, menu, UiEventType.MouseDown, 0, 10, belowPopupBottom)));
+        Assert.Null(fired);
+    }
+
+    [Fact]
+    public void TextIndent_And_ButtonTextIndent_DefaultToChatsBakedIconOffsets()
+    {
+        // G8: these used to be private consts (19f/19f-checkbox, 20f-LED);
+        // converting them to settable properties must not move chat's text.
+        var menu = new UiMenu();
+        Assert.Equal(19f, menu.TextIndent);
+        Assert.Equal(20f, menu.ButtonTextIndent);
+    }
+
+    [Fact]
+    public void TextIndent_And_ButtonTextIndent_AreSettable_ForIconLessMenus()
+    {
+        // Vendor's controller sets both to 0 (no checkbox/LED art to clear) —
+        // confirm the widget actually accepts the override.
+        var menu = new UiMenu { TextIndent = 0f, ButtonTextIndent = 0f };
+        Assert.Equal(0f, menu.TextIndent);
+        Assert.Equal(0f, menu.ButtonTextIndent);
+    }
 }