fix(chat): Campaign CH round 3 — SpewBox flush-top/font, /help exact print sequence

User-gate round 3 findings (a)-(c):

(a) SpewBox: TopOffset moves from the round-1 60px placeholder to 0 (flush
to the viewport top). SpewBoxController never wired DatFont/Font at all
before this round, so it silently rendered through the 15px debug
BitmapFont fallback; it now resolves retail dat Font 0x40000025
(MaxCharHeight=11px) through a new RetailUiRuntime.Assets accessor —
the smallest font id confirmed in use by any currently-imported retail
LayoutDesc fixture, cross-referenced against every
tests/AcDream.App.Tests/UI/Layout/fixtures/*.json dump and confirmed
against the installed DAT via AcDream.Cli dump-font-atlas. It is also the
chat window's own smallest font (the 0x2100006F floating-window 1/2/3/4
indicator badges), so both selection criteria the brief offered agree.
Both remain best-available approximations, not resolved retail values —
register row AP-178 updated accordingly.

(b)/(c) /help and /help death: round 2 extracted the individual retail
strings byte-exact but never traced ClientCommunicationSystem::DoHelp's
complete print sequence. Byte-swept DoHelp's own range plus the five
Summary-branch functions it calls into (HelpEmote/HelpSquelch/
HelpStatusGroup/HelpTextGroup/HelpAllGroup) against the PDB-paired
acclient.exe. Retail's real shape: bare /help prints exactly TWO scroll
entries (HelpPrefixNote, then the 13-item AvailableHelpListing built from
DoHelp's own literals and each group's Summary_HelpType branch, in exact
source order) — not the acdream-invented cheat sheet BuildHelpText()
built before. Any resolved /help <verb> gets the SAME two-entry shape:
HelpPrefixNote, then ForMoreInformationPrefix concatenated directly onto
the verb's own Detail text (retail's own unsubstituted "<command>"
literal, ported verbatim). ChatCommandRouter.EmitVerbHelp applies this
uniformly to every resolved verb, not just death. An unresolved verb now
shows retail's real "Unknown command" fallback text; that fallback types
0x1A (ClientLocal), which retail routes to the SpewBox exclusively — a
gap ChatVM's UI.Abstractions layer can't yet reach, filed as ISSUES #367
/ register AP-186 rather than left silently unregistered.

Jump-in-air (round 2's open item 1) was root-caused and fixed separately
at a5a7eb4f between rounds — recorded in the campaign ledger.

Debug suite (all projects): 12,329 passed / 4 skipped / 1 failed — the
one failure is issue #351, a pre-existing Debug-only streaming flake
confirmed reproducing identically on the pristine pre-round-3 commit via
git stash, not a regression. Release verification covers every project
reachable without rebuilding AcDream.App: a live client process (PID
15064) held its own Release binaries locked for the session and was not
killed per project policy — AcDream.UI.Abstractions.Tests (867/867, the
layer both /help fixes live in) plus every other non-App-dependent
project, all 0 failed. AcDream.App/AcDream.App.Tests/AcDream.Core.Tests
(the SpewBox fix's layer) are green in Debug only this session.

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

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

@@ -1,6 +1,8 @@
+using System.Collections.Generic;
 using AcDream.App.UI;
 using AcDream.Core.Chat;
 using AcDream.UI.Abstractions.Panels.SpewBox;
+using DatReaderWriter.Types;
 
 namespace AcDream.App.Tests.UI;
 
@@ -175,4 +177,79 @@ public sealed class SpewBoxControllerTests
 
         Assert.Empty(root.Children);
     }
+
+    // ── Campaign CH user-gate round 3 (2026-08-10), finding (a) ─────────
+
+    [Fact]
+    public void Construction_MountsFlushToTheViewportTop()
+    {
+        // The user reported the box "still not aligned all the way to the
+        // top" — TopOffset moved from the round-1 60px placeholder to 0.
+        var root = new UiRoot { Width = 1280f, Height = 720f };
+        using var controller = new SpewBoxController(root, new SpewBoxVM(new SpewBoxState()));
+
+        UiText text = Assert.IsType<UiText>(root.Children.OfType<UiText>().Single());
+        Assert.Equal(0f, text.Top);
+    }
+
+    [Fact]
+    public void Tick_KeepsTopFlushAndRecentersX_AcrossAResize()
+    {
+        var root = new UiRoot { Width = 1280f, Height = 720f };
+        var state = new SpewBoxState();
+        using var controller = new SpewBoxController(root, new SpewBoxVM(state));
+
+        state.Enqueue("resize me");
+        root.Tick(dt: 0d, nowMs: 1000L);
+
+        UiText text = Assert.IsType<UiText>(root.Children.OfType<UiText>().Single());
+        float widthBefore = root.Width;
+        Assert.Equal((widthBefore - 450f) / 2f, text.Left);
+        Assert.Equal(0f, text.Top);
+
+        // Simulate a window resize, then the next per-frame tick.
+        root.Width = 1920f;
+        root.Tick(dt: 0d, nowMs: 1016L);
+
+        Assert.Equal((1920f - 450f) / 2f, text.Left);
+        Assert.Equal(0f, text.Top); // top offset never depends on width
+    }
+
+    [Fact]
+    public void Construction_WithResolvedRetailFont_WiresDatFontOntoTheText()
+    {
+        // Campaign CH user-gate round 3: the retail dat font (id
+        // SpewBoxController.RetailFontId) is now actually WIRED, where
+        // before the controller never set DatFont/Font at all and silently
+        // fell through to the render context's default debug font.
+        var root = new UiRoot { Width = 1280f, Height = 720f };
+        var font = new UiDatFont(
+            fgTex: 1, fgW: 64, fgH: 64,
+            bgTex: 0, bgW: 0, bgH: 0,
+            lineHeight: 11f, baselineOffset: 9f,
+            glyphs: new Dictionary<char, FontCharDesc>());
+
+        using var controller = new SpewBoxController(
+            root, new SpewBoxVM(new SpewBoxState()), font, debugFont: null);
+
+        UiText text = Assert.IsType<UiText>(root.Children.OfType<UiText>().Single());
+        Assert.Same(font, text.DatFont);
+        Assert.Equal(11f, text.DatFont!.LineHeight);
+    }
+
+    [Fact]
+    public void Construction_WithoutAResolvedFont_FallsBackToTheSuppliedDebugFont()
+    {
+        // No installed-DAT font available (e.g. headless) -- the debug
+        // bitmap font parameter is still wired through, matching every
+        // other retained-UI controller's dat-font/debug-font pattern.
+        var root = new UiRoot { Width = 1280f, Height = 720f };
+
+        using var controller = new SpewBoxController(
+            root, new SpewBoxVM(new SpewBoxState()), font: null, debugFont: null);
+
+        UiText text = Assert.IsType<UiText>(root.Children.OfType<UiText>().Single());
+        Assert.Null(text.DatFont);
+        Assert.Null(text.Font);
+    }
 }