Fix: Stop repeated context-window notices when restoring sessions

src/MandoCode.Desktop.Tests/MandoCode.Desktop.Tests.csproj

@@ -56,6 +56,7 @@
          the file-naming convention is a real contract worth pinning; pure System.IO, no WinUI. -->
     <Compile Include="..\MandoCode.Desktop\Services\BuiltInBackgrounds.cs" Link="src\BuiltInBackgrounds.cs" />
     <Compile Include="..\MandoCode.Desktop\Services\TranscriptJournal.cs" Link="src\TranscriptJournal.cs" />
+    <Compile Include="..\MandoCode.Desktop\Services\ModelNoticeReplay.cs" Link="src\ModelNoticeReplay.cs" />
     <Compile Include="..\MandoCode.Desktop\Services\ConversationLog.cs" Link="src\ConversationLog.cs" />
     <!-- History's full-text matching + snippet extraction. Pure (text in, match out); the file reads
          and caching live in ConversationTextCache, which is NOT compiled here because it touches

src/MandoCode.Desktop.Tests/ModelNoticeReplayTests.cs

@@ -0,0 +1,32 @@
+using MandoCode.Desktop.Services;
+using Xunit;
+
+namespace MandoCode.Desktop.Tests;
+
+public class ModelNoticeReplayTests
+{
+    private const string Sizing = "Context window sized to 16k tokens for this model tier (applies from your next message).";
+    private static string Notice(string text, string kind = "dim") =>
+        $"<div class=\"notice-card {kind}\"><span class=\"notice-emoji\">ℹ️</span><span class=\"notice-text\">{text}</span></div>";
+
+    [Fact]
+    public void RepeatedRestoresDropAllHistoricalSetupNoticesButKeepConversation()
+    {
+        var answer = "<div class=\"assistant\">How can I help?</div>";
+        var history = new[] { answer, Notice(Sizing), Notice(Sizing), Notice(Sizing),
+            Notice("Cloud models run on ollama.com and need an active cloud subscription.") };
+        var replay = history.Where(h => !ModelNoticeReplay.IsTransient(h)).ToArray();
+        Assert.Equal(new[] { answer }, replay);
+        Assert.Equal(replay, replay.Where(h => !ModelNoticeReplay.IsTransient(h)));
+    }
+
+    [Fact]
+    public void QuotedWordingAndActualWarningsArePreserved()
+    {
+        Assert.False(ModelNoticeReplay.IsTransient($"<div class=\"assistant\">{Notice(Sizing)}</div>"));
+        Assert.False(ModelNoticeReplay.IsTransient($"<div class=\"user-echo\">{Sizing}</div>"));
+        Assert.False(ModelNoticeReplay.IsTransient(Notice(Sizing, "warn")));
+        Assert.False(ModelNoticeReplay.IsTransient(Notice("The context window is too small for this request.")));
+        Assert.False(ModelNoticeReplay.IsTransient(Notice("Project root changed to: C:\\project")));
+    }
+}

src/MandoCode.Desktop/Services/ModelNoticeReplay.cs

@@ -0,0 +1,19 @@
+using System.Text.RegularExpressions;
+
+namespace MandoCode.Desktop.Services;
+
+/// <summary>Old model setup notices describe a prior runtime, not the restored conversation.</summary>
+public static class ModelNoticeReplay
+{
+    public static bool IsTransient(string html)
+    {
+        // Match only standalone system notices. Keep user messages, assistant explanations,
+        // and errors even when they quote the same wording.
+        var match = Regex.Match(html,
+            "\\A<div class=\"notice-card dim\"><span class=\"notice-emoji\">[^<]*</span><span class=\"notice-text\">([^<]*)</span></div>\\z");
+        if (!match.Success) return false;
+        var text = match.Groups[1].Value;
+        return text == "Cloud models run on ollama.com and need an active cloud subscription."
+            || Regex.IsMatch(text, @"\AContext window sized to \d+k tokens for this model tier \(applies from your next message\)\.\z");
+    }
+}

src/MandoCode.Desktop/Services/TranscriptHtmlBuilder.cs

@@ -103,7 +103,8 @@ public static bool IsEphemeralStatus(string blockHtml) =>
         // Boot/progress narration — true only while it was happening. ("Project root
         // changed to: X" is deliberately NOT here: that's a real event, kept as history.)
         || blockHtml.Contains(">Rebuilding the AI session for the new project…<", StringComparison.Ordinal)
-        || blockHtml.Contains(">✓ Ready.<", StringComparison.Ordinal);
+        || blockHtml.Contains(">✓ Ready.<", StringComparison.Ordinal)
+        || ModelNoticeReplay.IsTransient(blockHtml);
 
     /// <summary>A compact status pill — a colored state dot, a bold primary value, and an
     /// optional dim qualifier. The dot replaces status emoji: crisp and theme-aware.

src/MandoCode.Desktop/ViewModels/ChatController.cs

@@ -1583,7 +1583,8 @@ private async Task ApplyModelSwitchAsync(string modelTag)
         if (recommendedCtx > 0 && recommendedCtx != _config.ContextLength)
         {
             _config.ContextLength = recommendedCtx;
-            _transcript.Append(_html.Dim($"Context window sized to {recommendedCtx / 1024}k tokens for this model tier (applies from your next message)."));
+            if (!DeferModelAnnouncement)
+                _transcript.Append(_html.Dim($"Context window sized to {recommendedCtx / 1024}k tokens for this model tier (applies from your next message)."));
         }
 
         _busy.Start("Switching model...");
@@ -1609,7 +1610,8 @@ private async Task ApplyModelSwitchAsync(string modelTag)
         if (MandoCodeConfig.IsCloudModel(modelTag) && !_cloudNoticeShown)
         {
             _cloudNoticeShown = true;
-            _transcript.Append(_html.Dim("Cloud models run on ollama.com and need an active cloud subscription."));
+            if (!DeferModelAnnouncement)
+                _transcript.Append(_html.Dim("Cloud models run on ollama.com and need an active cloud subscription."));
         }
 
         // Only mention the cleared context — and offer a snapshot — when there was actually a