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/RetailUiRuntime.cs

@@ -3853,7 +3853,8 @@ public sealed class RetailUiRuntime : IDisposable
                     xml,
                     panel.Binding,
                     _bindings.Assets.ResolveSprite,
-                    _bindings.Assets.Controls);
+                    _bindings.Assets.Controls,
+                    _bindings.Assets.DefaultFont);
                 Host.Root.AddChild(element);
                 _bindings.Plugins.CompleteMount(panel, Host.Root, element);
                 Console.WriteLine($"[D.2b] plugin UI panel loaded: {panel.MarkupPath}");