fix(chat): #363 — retail 0x1A typing for command refusals via the interface-text seam

ChatVM gains an OnInterfaceText hook + ShowInterfaceText(text), the
App-layer composition wires it to RuntimeCommunicationState.AddText,
and ChatCommandRouter routes every retail-0x1A command refusal through
it instead of the chat log's 0x00 sink. UI.Abstractions still never
references Runtime directly; unwired hosts (headless, tests) fall back
to the chat log tagged ClientLocal so no text is ever silently lost.

Reclassified per register row AP-183 (DoChannelList/On/Off, DoAllegiance,
DoHouseAvailableList — the last also corrected to retail's own bad-house-
type string instead of a synthesized "Usage:" line) and newly wired two
sites that previously showed nothing at all (DoStupidChannelHack's bare
legacy-channel-verb refusal, DoReply's message-but-no-last-teller
refusal). The generic bad-args fallback now resolves WeenieErrorMessages
0x026 ("That is not a valid command.", retail's HandleFailureEvent(0x26))
instead of synthesizing "Usage: {Usage}". DoSpeaker/DoEndurance/DoTitle
are untouched — already correct at 0x00.

Also closes #367 (DoHelp's "Unknown command" fallback and the degenerate-
prefix refusal now reach the SpewBox too) and retires register row
AP-186, whose own filing proposed exactly this seam shape.

Full Release suite: 12,542 passed / 4 skipped / 0 failed (baseline
12,466/4/0 at ff2784ea).

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

src/AcDream.UI.Abstractions/Panels/Chat/ChatVM.cs

@@ -73,6 +73,21 @@ public sealed class ChatVM : IDisposable
     /// </summary>
     public Func<Vector3>? PositionProvider { get; init; }
 
+    /// <summary>
+    /// Optional hook routing retail-<c>0x1A</c> (<see
+    /// cref="RetailLogTextType.ClientLocal"/>) interface text — command
+    /// refusals and bad-argument usage lines — to the SpewBox instead of
+    /// the chat transcript. <c>AcDream.UI.Abstractions</c> must stay
+    /// Runtime-independent (Code Structure Rules), so it cannot call
+    /// <c>RuntimeCommunicationState.AddText</c> directly; the App-layer
+    /// composition host wires this the same way it wires
+    /// <see cref="FpsProvider"/>/<see cref="PositionProvider"/>. Closes
+    /// ISSUES.md #367 / register row AP-186 — <see cref="ChatCommandRouter"/>
+    /// no longer has to render every <c>0x1A</c> refusal through the chat
+    /// scroll.
+    /// </summary>
+    public Action<string>? OnInterfaceText { get; init; }
+
     /// <summary>Monotonic revision of the underlying transcript content.</summary>
     public long Revision => _log.Revision;
 
@@ -139,6 +154,33 @@ public sealed class ChatVM : IDisposable
     /// </remarks>
     public void ShowSystemMessage(string text) => _log.OnSystemMessage(text, chatType: 0x00u);
 
+    /// <summary>
+    /// Route a retail-<c>0x1A</c> (<see cref="RetailLogTextType.ClientLocal"/>)
+    /// command refusal / usage line to the SpewBox — retail's
+    /// <c>ClientSystem::AddTextToScroll(text, 0x1A, 1, windowId) @0x00563C50</c>
+    /// destination for this text type is the SpewBox exclusively, never a
+    /// chat window (<c>docs/research/2026-08-09-chat-retail-interface-text.md</c>
+    /// §2.1/§2.2).
+    /// </summary>
+    /// <remarks>
+    /// Prefers <see cref="OnInterfaceText"/> when the App-layer host wired
+    /// it (the production graphical client). When unwired — headless, the
+    /// automation probe runner, or a test fixture that only exercises the
+    /// pure UI.Abstractions layer — the text still needs to reach the
+    /// player somewhere, so it falls back to the ordinary chat transcript
+    /// tagged with the real <see cref="RetailLogTextType.ClientLocal"/>
+    /// color rather than being silently dropped. That fallback lands in
+    /// the wrong PANEL (chat instead of SpewBox) but keeps the right TYPE
+    /// and never loses the line — the safe default issue #363 requires.
+    /// </remarks>
+    public void ShowInterfaceText(string text)
+    {
+        if (OnInterfaceText is { } hook)
+            hook(text);
+        else
+            _log.OnSystemMessage(text, chatType: (uint)RetailLogTextType.ClientLocal);
+    }
+
     /// <summary>
     /// Drain the chat log. Used by the /clear client-side command.
     /// </summary>