fix(runtime,ui): Campaign LA gate round 2 — world name reads durably; dialogs center on the canvas

Two live-integration gaps the ef96c554 unit tests could not see:

1. World box stayed empty against ACE: ServerName (0xF7E1) arrives in the
   SAME connect batch as CharacterList, so ServerNameReceived fires during
   the handshake pump BEFORE the controller binding subscribes - the
   event-only wiring proved the state and controller but never the live
   ordering. StartCore now reads the durable WorldSession.ServerInfo after
   connect exactly like the roster (ILiveSessionOperations.GetServerInfo,
   default interface method so no fake breaks); the event remains for
   post-connect updates. Pinned by a Start-level test.

2. The exit confirmation rendered far right of the screen: all three
   retail dialog views centered against the raw window size while the
   active screen lays out in the fixed 800x600 canvas - center-of-1920
   is canvas-760, which the stretch pushes off-center. Views now center
   against UiRoot.EffectiveCanvasSize (canvas while a pre-world screen is
   active, window otherwise). Pinned by growing the window over the fixed
   canvas in the exit-dialog test and asserting the scrim spans the canvas
   with the popup centered at 400.

Runtime 1666, App 5100+6 skips, green.

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

tests/AcDream.Runtime.Tests/Session/LiveSessionControllerTests.cs

@@ -113,6 +113,13 @@ public sealed class LiveSessionControllerTests
             return Characters;
         }
 
+        /// <summary>Gate-round-2 world-name live fix: mirrors the durable
+        /// post-connect read the production path performs (the wire event
+        /// fires during the handshake, before any subscriber exists).</summary>
+        public ServerName.Parsed? ServerInfo { get; set; }
+
+        public ServerName.Parsed? GetServerInfo(WorldSession session) => ServerInfo;
+
         public void StartCharacterSelectionReceive(WorldSession session) =>
             calls.Add("start-character-selection-receive");
 
@@ -349,6 +356,33 @@ public sealed class LiveSessionControllerTests
         Assert.True(host.CommandBuses[0].Active);
     }
 
+    /// <summary>
+    /// Gate-round-2 live fix: ACE sends ServerName (0xF7E1) in the SAME
+    /// connect batch as CharacterList, so the event fires during the
+    /// handshake pump before the binding subscribes — the World box stayed
+    /// empty against a live server while the event-only unit tests passed.
+    /// Start must read the durable ServerInfo after connect, exactly like
+    /// the roster.
+    /// </summary>
+    [Fact]
+    public void Start_AppliesWorldNameFromDurableServerInfoAfterConnect()
+    {
+        var calls = new List<string>();
+        var operations = new TestOperations(calls)
+        {
+            ServerInfo = new ServerName.Parsed(1, 128, "sawato"),
+        };
+        var host = new TestHost(calls);
+        var controller = new LiveSessionController(operations);
+
+        LiveSessionStartResult result = controller.Start(LiveOptions(), host);
+
+        Assert.Equal(LiveSessionStartStatus.Connected, result.Status);
+        Assert.Equal(
+            "sawato",
+            controller.CharacterSelectionState.View.Snapshot.WorldName);
+    }
+
     [Fact]
     public void Start_ReportsRosterFromCharacterListBeforeSelection()
     {