Enhance MemoryCacheExtensions and update HistoryController

- Modified `GetEnumAsDictionary` to accept a key and ignores for better caching and filtering of enum values.
- Updated XML documentation in `HistoryController.cs` to correct status code descriptions.
- Adjusted `GetEnvelopeStatus` to use the new parameters for improved control over cached enum values.

EnvelopeGenerator.Extensions/MemoryCacheExtensions.cs

@@ -6,11 +6,15 @@ public static class MemoryCacheExtensions
 {
     private static readonly Guid BaseId = Guid.NewGuid();
 
-    public static IDictionary<string, int> GetEnumAsDictionary<TEnum>(this IMemoryCache memoryCache)
+    public static IDictionary<string, int> GetEnumAsDictionary<TEnum>(this IMemoryCache memoryCache, string key = "", params IEnumerable<TEnum>[] ignores)
         where TEnum : Enum
-        => memoryCache.GetOrCreate(BaseId + typeof(TEnum).FullName, _ =>
-               Enum.GetValues(typeof(TEnum))
+        => memoryCache.GetOrCreate(BaseId + typeof(TEnum).FullName + key, _ =>
+        {
+            List<TEnum> mergedIgnores = ignores.SelectMany(x => x).ToList();
+            return Enum.GetValues(typeof(TEnum))
                    .Cast<TEnum>()
-                   .ToDictionary(e => e.ToString(), e => Convert.ToInt32(e)))
+                   .Where(e => !mergedIgnores.Contains(e))
+                   .ToDictionary(e => e.ToString(), e => Convert.ToInt32(e));
+        })
            ?? throw new InvalidOperationException($"Failed to cache or retrieve enum dictionary for type '{typeof(TEnum).FullName}'.");
 }