fix(mosstank): unclickable button, empty skill list, dev font, and chat output

Four defects from the first in-world look, three of them with a definite root
cause rather than a plausible one.

**The Buff button did nothing.** Not a hit-testing problem -- the pointer found
the button perfectly. UiRoot's press handling asks the pressed widget whether
it owns the pointer; a widget that does not claim the press falls through to
"move the ancestor window", and a window drag returns early on release without
ever emitting a Click. UiButton and UiClickablePanel both override
HandlesClick for exactly this reason; UiSimpleButton never did. Latent since
that class was written, and invisible until it was put inside a draggable
window -- which is precisely what a markup plugin panel is.

Found by reproducing it headlessly through the real UiRoot dispatcher rather
than by reasoning about it: MarkupPanelClickTests drives press-and-release over
the button and asserts the bound action ran, with a separate test asserting the
pointer finds the button at all, so a future failure says which half broke.
My earlier guess -- that a modal at character select was swallowing the click
-- was wrong, and the screenshot of the panel live in world disproved it.

**"0 trained skills".** The skill-name table was read in OnLoad *before*
GameWindowCompositionPipeline.Run, which is what publishes the DAT collection,
so _dats was still null, the whole block was skipped, and the surface reported
an empty skill list with nothing to explain it. Bound in PublishDatCollection
instead -- the moment the data exists -- so it cannot run early again whatever
the phase ordering does, and a genuinely missing SkillTable now says so.

**Plugin text used the development bitmap font.** UiLabel and UiSimpleButton
gained a DatFont, and MarkupDocument now takes the retail interface font from
the host, so plugin panels render through the same glyph path (including
retail's two-plane outline) as authored panels.

**MossTank now writes to chat.** New BCL-only IPluginChat routes to retail's
ClientLocal log type (0x1A) -- the channel the client uses for its own notices,
local to this client, so a plugin cannot speak in the player's name. MossTank
announces the start, the finish with a cast count, and a stall.

Not addressed here: the cursor showing blue rather than amber. Traced but not
fixed -- CursorFeedbackController picks the cursor family from combat mode, and
CombatMode.Magic selects the blue Magic cursor where Default is amber. That is
a combat-mode question, unrelated to this change, and worth its own look rather
than a speculative fix folded in here.

Solution builds clean; 14,437 tests pass on the standard hermetic lane filter,
0 failures.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/AcDream.App/UI/MarkupDocument.cs

@@ -18,9 +18,14 @@ public static class MarkupDocument
     /// <param name="binding">Object whose public properties are bound to <c>{PropName}</c> attributes.</param>
     /// <param name="resolve">Surface id → (GL handle, width, height) for chrome sprites.</param>
     /// <param name="style">Optional controls.ini stylesheet for the title color.</param>
+    /// <param name="datFont">
+    /// Retail interface font. Supplied by the host so plugin panels render
+    /// their text through the same glyph path as authored panels; without it
+    /// they fall back to the development bitmap font and look foreign.
+    /// </param>
     public static UiNineSlicePanel Build(
         string xml, object binding, Func<uint, (uint, int, int)> resolve,
-        ControlsIni? style = null)
+        ControlsIni? style = null, UiDatFont? datFont = null)
     {
         var root = XDocument.Parse(xml).Root ?? throw new FormatException("empty markup");
         if (root.Name.LocalName != "panel")
@@ -62,7 +67,10 @@ public static class MarkupDocument
         if (!string.IsNullOrEmpty(title))
         {
             Vector4 tc = style is not null && style.TryColor("title", "color", out var c) ? c : Vector4.One;
-            panel.AddChild(new UiLabel { Text = title, Left = 8, Top = 4, TextColor = tc });
+            panel.AddChild(new UiLabel
+            {
+                Text = title, Left = 8, Top = 4, TextColor = tc, DatFont = datFont,
+            });
         }
 
         foreach (var el in root.Elements())
@@ -102,6 +110,7 @@ public static class MarkupDocument
                         Left = F(el, "x"),
                         Top = F(el, "y"),
                         TextSource = BindString((string?)el.Attribute("text"), binding),
+                        DatFont = datFont,
                     };
                     if (el.Attribute("color") is not null)
                         label.TextColor = Color((string?)el.Attribute("color"));
@@ -133,6 +142,7 @@ public static class MarkupDocument
                         Width = F(el, "w"),
                         Height = F(el, "h"),
                         Text = (string?)el.Attribute("text") ?? string.Empty,
+                        DatFont = datFont,
                     };
                     // A bound caption lets the button re-label itself (Buff /
                     // Stop) from the same binding object.