feat(ui): color and acknowledge pinned log errors

Add independent AppLog message types and explicit Class 1/2 severity. Wrap and color log rows, pin Class 1 above Class 2, and let acknowledgement return entries to the current-launch timeline without changing file format or rotation.

Ref: https://logtape.org/manual/levels

Helpers/AppLog.cs

@@ -2,6 +2,24 @@ using System.IO;
 
 namespace ytLive.Helpers;
 
+/// <summary>Presentation category; independent from the entry's attention class.</summary>
+public enum AppLogMessageType
+{
+    Information,
+    Success,
+    Warning,
+    Error,
+}
+
+/// <summary>Explicit attention priority, assigned by the writer rather than inferred from text or source.</summary>
+public enum AppLogErrorClass
+{
+    /// <summary>Fatal or unhandled failure; highest priority.</summary>
+    Class1 = 1,
+    /// <summary>Recoverable failure that still requires attention.</summary>
+    Class2 = 2,
+}
+
 /// <summary>
 /// Minimal file logger used to diagnose startup/shutdown crashes on Windows,
 /// where the WPF app has no visible console. Writes to
@@ -39,6 +57,15 @@ public static class AppLog
     }
 
     public static void Write(string message)
+        => Write(message, AppLogMessageType.Information);
+
+    public static void WriteWarning(string message)
+        => Write(message, AppLogMessageType.Warning);
+
+    public static void WriteSuccess(string message)
+        => Write(message, AppLogMessageType.Success);
+
+    public static void Write(string message, AppLogMessageType type, AppLogErrorClass? errorClass = null)
     {
         try
         {
@@ -46,7 +73,9 @@ public static class AppLog
             {
                 var entry = new AppLogEntry(
                     ++_nextSequence,
-                    $"{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff} {message}");
+                    $"{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff} {message}",
+                    type,
+                    errorClass);
                 CurrentLaunchEntries.Add(entry);
                 if (CurrentLaunchEntries.Count > CurrentLaunchEntryLimit)
                     CurrentLaunchEntries.RemoveAt(0);
@@ -65,8 +94,29 @@ public static class AppLog
 
     public static void Write(Exception exception, string message)
     {
-        Write($"{message}: {exception}");
+        Write($"{message}: {exception}", AppLogMessageType.Error);
     }
+
+    public static void Write(Exception exception, string message, AppLogErrorClass errorClass)
+        => Write($"{message}: {exception}", AppLogMessageType.Error, errorClass);
 }
 
-public sealed record AppLogEntry(long Sequence, string Text);
+public sealed record AppLogEntry(long Sequence, string Text, AppLogMessageType Type,
+    AppLogErrorClass? ErrorClass)
+{
+    public string? ErrorClassLabel => ErrorClass switch
+    {
+        AppLogErrorClass.Class1 => "CLASS 1",
+        AppLogErrorClass.Class2 => "CLASS 2",
+        _ => null,
+    };
+
+    public string TypeLabel => ErrorClassLabel ?? Type switch
+    {
+        AppLogMessageType.Information => "INFO",
+        AppLogMessageType.Success => "SUCCESS",
+        AppLogMessageType.Warning => "WARNING",
+        AppLogMessageType.Error => "ERROR",
+        _ => Type.ToString().ToUpperInvariant(),
+    };
+}