fix(vt): list column fix round 1/11 — text column optional onclick

None of VTank's eight HudList instances relies on row selection
(PluginCore.cs Monsters/Items/Meta/Route/Buffs/Consumables cell
handlers) — every real text cell is an action target. Add an optional
onclick="{Action<int>}" to <column type="text">: when present, a click
fires it with the row index INSTEAD of selecting; when absent, the
original select-the-row behavior is unchanged. BuildListColumn now
takes the column's own index (used for its onclick throw message and
threaded through for the rest of the fix round's column-context
messages); the unknown-<column type> throw also picked up the index
as a side effect of that signature change.

New tests (MarkupListColumnsTests): the onclick attribute binds and
falls back correctly when absent, a malformed onclick throws at Build,
and a click actually reaches the bound callback instead of firing
SelectionChanged — each shown to fail first (missing TextClicked
member / no 4-arg Text() overload before the production change).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/AcDream.App/UI/MarkupDocument.cs

@@ -553,7 +553,7 @@ public static class MarkupDocument
                 if (listUsesColumns)
                 {
                     list.Columns = listChildren
-                        .Select(columnEl => BuildListColumn(columnEl, binding, icons))
+                        .Select((columnEl, index) => BuildListColumn(columnEl, binding, icons, index))
                         .ToList();
                 }
                 else
@@ -994,7 +994,7 @@ public static class MarkupDocument
     /// stays null (draws nothing) rather than ever pointing at a null resolver.
     /// </summary>
     private static UiMarkupListColumn BuildListColumn(
-        XElement columnEl, object binding, IMarkupIconResolver? icons)
+        XElement columnEl, object binding, IMarkupIconResolver? icons, int index)
     {
         string? type = (string?)columnEl.Attribute("type");
         float width = F(columnEl, "width");
@@ -1008,7 +1008,21 @@ public static class MarkupDocument
                 Func<IReadOnlyList<uint>>? colorsSource = colorsAttr is null
                     ? null
                     : BindUintList(colorsAttr, binding, "column colors");
-                return UiMarkupListColumn.Text(width, textSource, colorsSource);
+                // Fix round finding 1: optional onclick — a text cell that
+                // declares one fires it with the row index instead of
+                // selecting; one that doesn't keeps the original
+                // select-on-click behavior. Same "resolve if binding-shaped,
+                // throw only if malformed" rule as the list's own onchange
+                // above — omitting the attribute entirely is fine.
+                string? textOnClickAttr = (string?)columnEl.Attribute("onclick");
+                Action<int>? textOnClick = BindIntAction(textOnClickAttr, binding);
+                if (textOnClickAttr is not null && textOnClick is null)
+                {
+                    throw new FormatException(
+                        $"{ColumnContext(index, "text", "onclick")} did not resolve to an "
+                        + $"Action<int> property on {binding.GetType().Name}");
+                }
+                return UiMarkupListColumn.Text(width, textSource, colorsSource, textOnClick);
             }
             case "check":
             {
@@ -1033,10 +1047,21 @@ public static class MarkupDocument
             }
             default:
                 throw new FormatException(
-                    $"unknown <column type=\"{type}\"> (expected text, check, or icon)");
+                    $"column[{index}] has unknown type=\"{type}\" (expected text, check, or icon)");
         }
     }
 
+    /// <summary>
+    /// Fix round finding 5: every column-attribute throw message identifies
+    /// the offending column by position and declared type
+    /// (<c>column[2] type="check" values</c>) rather than the generic
+    /// <c>"column values"</c> the initial slice used — a plugin author with
+    /// several columns of the same <c>type</c> needs the index to find which
+    /// one is wrong.
+    /// </summary>
+    private static string ColumnContext(int index, string type, string attribute) =>
+        $"column[{index}] type=\"{type}\" {attribute}";
+
     private static bool IsBinding(string value) =>
         value.Length > 2 && value[0] == '{' && value[^1] == '}';
 

src/AcDream.App/UI/UiMarkupList.cs

@@ -360,10 +360,16 @@ public sealed class UiMarkupList : UiElement
             switch (columns[c].Kind)
             {
                 case UiMarkupListColumnKind.Text:
-                    // Text-column click selects — the list's own
-                    // selected/onchange, unchanged in meaning from the
-                    // single-column list.
-                    SelectionChanged?.Invoke(index);
+                    // Fix round finding 1: a text column with its own
+                    // onclick fires THAT instead of selecting — none of
+                    // VTank's eight lists actually uses row selection, every
+                    // real text cell is an action target. A text column
+                    // without onclick keeps the original select-the-row
+                    // behavior (the list's own selected/onchange).
+                    if (columns[c].TextClicked is { } onTextClick)
+                        onTextClick(index);
+                    else
+                        SelectionChanged?.Invoke(index);
                     break;
                 case UiMarkupListColumnKind.Check:
                     // A click in a check/icon column fires that column's own

src/AcDream.App/UI/UiMarkupListColumn.cs

@@ -46,6 +46,18 @@ public sealed class UiMarkupListColumn
     /// column draws with the list's <see cref="UiMarkupList.TextColor"/>.
     /// </summary>
     public Func<IReadOnlyList<uint>>? ColorsSource { get; init; }
+    /// <summary>
+    /// Fix round finding 1: optional <c>onclick="{Action&lt;int&gt;}"</c> on a
+    /// text column. Fired with the ROW INDEX on a click anywhere in the cell
+    /// INSTEAD of selecting the row, when present. Null (the default — no
+    /// <c>onclick</c> attribute at all) keeps today's original behavior: a
+    /// click in this cell selects the row and fires the list's own
+    /// <c>onchange</c>, exactly as before this fix. None of VTank's eight
+    /// lists actually uses row selection — every real text cell is an action
+    /// target — but the select-on-click default stays for any acdream markup
+    /// that already relies on it.
+    /// </summary>
+    public Action<int>? TextClicked { get; init; }
 
     // ── check ─────────────────────────────────────────────────────────────
     /// <summary><c>&lt;column type="check" values="{IReadOnlyList&lt;bool&gt;}"&gt;</c>.</summary>
@@ -79,12 +91,14 @@ public sealed class UiMarkupListColumn
     public static UiMarkupListColumn Text(
         float width,
         Func<IReadOnlyList<string>> textSource,
-        Func<IReadOnlyList<uint>>? colorsSource) => new()
+        Func<IReadOnlyList<uint>>? colorsSource,
+        Action<int>? onClick = null) => new()
     {
         Kind = UiMarkupListColumnKind.Text,
         Width = width,
         TextSource = textSource,
         ColorsSource = colorsSource,
+        TextClicked = onClick,
     };
 
     public static UiMarkupListColumn Check(

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

@@ -324,6 +324,71 @@ public sealed class MarkupListColumnsTests
         Assert.Throws<FormatException>(() => MarkupDocument.Build(xml, binding, Sprite));
     }
 
+    // ── Fix round: text column optional onclick (fix item 1) ────────────────
+
+    [Fact]
+    public void TextColumn_OptionalOnclickAttribute_BindsAndDoesNotBreakWithoutIt()
+    {
+        var binding = new ThreeColumnBinding();
+        const string withOnclick =
+            "<panel x=\"0\" y=\"0\" w=\"200\" h=\"100\">" +
+            "<list x=\"0\" y=\"0\" w=\"180\" h=\"60\" selected=\"{Selected}\">" +
+            "  <column type=\"text\" width=\"80\" items=\"{Names}\" onclick=\"{ClickIcon}\"/>" +
+            "</list></panel>";
+        var panelWith = MarkupDocument.Build(withOnclick, binding, Sprite);
+        var listWith = Assert.IsType<UiMarkupList>(panelWith.Children[0]);
+        Assert.NotNull(listWith.Columns![0].TextClicked);
+
+        const string withoutOnclick =
+            "<panel x=\"0\" y=\"0\" w=\"200\" h=\"100\">" +
+            "<list x=\"0\" y=\"0\" w=\"180\" h=\"60\" selected=\"{Selected}\">" +
+            "  <column type=\"text\" width=\"80\" items=\"{Names}\"/>" +
+            "</list></panel>";
+        var panelWithout = MarkupDocument.Build(withoutOnclick, binding, Sprite);
+        var listWithout = Assert.IsType<UiMarkupList>(panelWithout.Children[0]);
+        Assert.Null(listWithout.Columns![0].TextClicked);
+    }
+
+    [Fact]
+    public void TextColumn_MalformedOnclickAttribute_ThrowsAtBuild()
+    {
+        var binding = new ThreeColumnBinding();
+        const string xml =
+            "<panel x=\"0\" y=\"0\" w=\"200\" h=\"100\">" +
+            "<list x=\"0\" y=\"0\" w=\"180\" h=\"60\" selected=\"{Selected}\">" +
+            "  <column type=\"text\" width=\"80\" items=\"{Names}\" onclick=\"notabinding\"/>" +
+            "</list></panel>";
+
+        var ex = Assert.Throws<FormatException>(() => MarkupDocument.Build(xml, binding, Sprite));
+        Assert.Contains("column[0] type=\"text\" onclick", ex.Message);
+    }
+
+    [Fact]
+    public void ClickInTextColumn_WithOnclick_FiresItInsteadOfSelecting()
+    {
+        var clicked = new List<int>();
+        var selections = new List<int>();
+        var list = new UiMarkupList
+        {
+            Width = 60f, Height = 200f, RowHeight = 20f,
+            SelectedIndexSource = () => -1,
+            SelectionChanged = row => selections.Add(row),
+            Columns = new[]
+            {
+                UiMarkupListColumn.Text(
+                    60f, () => new[] { "a", "b", "c" }, null, row => clicked.Add(row)),
+            },
+        };
+        var (_, ctx) = MakeContext(200f, 200f);
+        list.DrawSelfAndChildren(ctx);
+
+        // Row 1 (y = 20..40).
+        list.OnEvent(new UiEvent { Type = UiEventType.MouseDown, Data1 = 10, Data2 = 25 });
+
+        Assert.Equal(new[] { 1 }, clicked);
+        Assert.Empty(selections);
+    }
+
     // ── Draw-level: column x-offsets, check glyph, icon, clipping ────────────
 
     private static (TextRenderer renderer, UiRenderContext ctx) MakeContext(float w, float h)