feat(launcher): stabilize prepared content updates

tests/AcDream.Launcher.Core.Tests/Launching/SessionConfigComposerTests.cs

@@ -39,6 +39,34 @@ public sealed class SessionConfigComposerTests
             LoginCommands = ["/tell someone, hi"],
         };
 
+    [Fact]
+    public void PendingClientCompatibilityCannotComposePlayOrProbeSession()
+    {
+        LauncherInstallRecord pending = Install with
+        {
+            RequiresClientCompatibilityConfirmation = true,
+        };
+
+        InvalidOperationException play = Assert.Throws<InvalidOperationException>(() =>
+            SessionConfigComposer.Compose(
+                Server(),
+                Account(),
+                Character(LaunchMode.Gui),
+                pending,
+                Paths,
+                "pending-play"));
+        InvalidOperationException probe = Assert.Throws<InvalidOperationException>(() =>
+            SessionConfigComposer.ComposeProbe(
+                Server(),
+                Account(),
+                pending,
+                Paths,
+                "pending-probe"));
+
+        Assert.Contains("matching client", play.Message, StringComparison.OrdinalIgnoreCase);
+        Assert.Contains("matching client", probe.Message, StringComparison.OrdinalIgnoreCase);
+    }
+
     [Fact]
     public void GuiModeIncludesCharacterSelectorAndOmitsPolicy()
     {