Use consistent meeting artifact filenames

MeetingAssistant/MeetingNotes/MarkdownMeetingNoteStore.cs

@@ -35,7 +35,7 @@ public sealed class MarkdownMeetingNoteStore : IMeetingNoteStore
         Directory.CreateDirectory(folder);
 
         var path = string.IsNullOrWhiteSpace(note.Path)
-            ? Path.Combine(folder, $"{DateTimeOffset.Now:yyyyMMdd-HHmmss-fffffff}-{Slugify(note.Frontmatter.Title)}.md")
+            ? Path.Combine(folder, MeetingArtifactFileNames.Create(note.Frontmatter.StartTime ?? DateTimeOffset.Now, MeetingArtifactFileNames.Note))
             : note.Path;
         var frontmatter = PrepareFrontmatter(note.Frontmatter, path);
         var content = Render(frontmatter, note.UserNotes);
@@ -108,16 +108,6 @@ public sealed class MarkdownMeetingNoteStore : IMeetingNoteStore
         return string.Join(Environment.NewLine, lines);
     }
 
-    private static string Slugify(string value)
-    {
-        var slug = new string(value
-            .ToLowerInvariant()
-            .Select(character => char.IsLetterOrDigit(character) ? character : '-')
-            .ToArray());
-        slug = string.Join("-", slug.Split('-', StringSplitOptions.RemoveEmptyEntries));
-        return string.IsNullOrWhiteSpace(slug) ? "meeting" : slug;
-    }
-
     private static string EscapeScalar(string value)
     {
         return string.IsNullOrWhiteSpace(value) ? "\"\"" : EscapeListItem(value);