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/UiPanel.cs

@@ -78,10 +78,26 @@ public class UiLabel : UiElement
     /// </summary>
     public Func<string?>? TextSource { get; set; }
 
+    /// <summary>
+    /// Retail dat font. When set the label renders through the same glyph path
+    /// every authored panel uses, so plugin text matches the rest of the
+    /// interface instead of falling back to the development bitmap font.
+    /// </summary>
+    public UiDatFont? DatFont { get; set; }
+
+    /// <summary>Two-plane glyph outline, as retail draws interface text.</summary>
+    public bool Outline { get; set; } = true;
+
     public UiLabel() { ClickThrough = true; }
 
     protected override void OnDraw(UiRenderContext ctx)
-        => ctx.DrawString(TextSource?.Invoke() ?? Text, 0, 0, TextColor);
+    {
+        string text = TextSource?.Invoke() ?? Text;
+        if (DatFont is { } dat)
+            ctx.DrawStringDat(dat, text, 0, 0, TextColor, Outline);
+        else
+            ctx.DrawString(text, 0, 0, TextColor);
+    }
 }
 
 /// <summary>
@@ -104,8 +120,26 @@ public class UiSimpleButton : UiPanel
     /// without the binding object touching UI objects.
     /// </summary>
     public Func<string?>? TextSource { get; set; }
+
+    /// <summary>Retail dat font for the caption; see <see cref="UiLabel.DatFont"/>.</summary>
+    public UiDatFont? DatFont { get; set; }
+
+    /// <summary>Two-plane glyph outline, as retail draws interface text.</summary>
+    public bool Outline { get; set; } = true;
+
     public event System.Action? Click;
 
+    /// <summary>
+    /// Without this the button is unclickable inside any draggable window.
+    /// 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", which swallows the release and never emits
+    /// a Click. <see cref="UiButton"/> and <see cref="UiClickablePanel"/>
+    /// already declare it — this one did not, which is why a markup plugin
+    /// panel's button did nothing while its hit-test was perfectly fine.
+    /// </summary>
+    public override bool HandlesClick => true;
+
     public UiSimpleButton()
     {
         BackgroundColor = new Vector4(0.1f, 0.1f, 0.15f, 0.8f);
@@ -126,8 +160,19 @@ public class UiSimpleButton : UiPanel
     {
         base.OnDraw(ctx);
         string caption = TextSource?.Invoke() ?? Text;
-        if (caption.Length == 0 || ctx.DefaultFont is null) return;
+        if (caption.Length == 0) return;
 
+        if (DatFont is { } dat)
+        {
+            float datW = dat.MeasureWidth(caption);
+            ctx.DrawStringDat(
+                dat, caption,
+                (Width - datW) * 0.5f, (Height - dat.LineHeight) * 0.5f,
+                TextColor, Outline);
+            return;
+        }
+
+        if (ctx.DefaultFont is null) return;
         float textW = ctx.DefaultFont.MeasureWidth(caption);
         float tx = (Width  - textW) * 0.5f;
         float ty = (Height - ctx.DefaultFont.LineHeight) * 0.5f;