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

Services/ChannelStatsService.cs

@@ -1,6 +1,8 @@
 using System.Net.Http;
 using System.Text.Json;
 using ytLive.Models;
+using AppLogErrorClass = ytLive.Helpers.AppLogErrorClass;
+using AppLogMessageType = ytLive.Helpers.AppLogMessageType;
 using AppLog = ytLive.Helpers.AppLog;
 
 namespace ytLive.Services;
@@ -54,7 +56,8 @@ public class ChannelStatsService
             // (insufficientPermissions / quotaExceeded / …) — the bare code was
             // undiagnosable for the 2026-09-23 auditDetails 403.
             var errorBody = await response.Content.ReadAsStringAsync();
-            AppLog.Write($"YPP stats: channels.list failed ({(int)response.StatusCode}): {errorBody}");
+            AppLog.Write($"YPP stats: channels.list failed ({(int)response.StatusCode}): {errorBody}",
+                AppLogMessageType.Error, AppLogErrorClass.Class2);
             return null;
         }
 
@@ -107,7 +110,8 @@ public class ChannelStatsService
             $"{ApiBase}/playlistItems?part=snippet&playlistId={Uri.EscapeDataString(uploadsPlaylistId)}&maxResults=50");
         if (!response.IsSuccessStatusCode)
         {
-            AppLog.Write($"YPP stats: playlistItems.list failed ({(int)response.StatusCode})");
+            AppLog.Write($"YPP stats: playlistItems.list failed ({(int)response.StatusCode})",
+                AppLogMessageType.Error, AppLogErrorClass.Class2);
             return 0;
         }
 
@@ -129,4 +133,4 @@ public class ChannelStatsService
         }
         return count;
     }
-}
+}