Add PageNoteButton to various components for enhanced note management

WebApp/Components/Pages/NoteEditDialog.razor

@@ -6,7 +6,7 @@
 @inject ISnackbar Snackbar
 @inject IDialogService DialogService
 
-<MudDialog>
+<MudDialog Class="@MarkdownHelper.GetNoteColorClass(_note.Id)">
     <DialogContent>
         <MudStack Spacing="3">
             <MudTextField @bind-Value="_note.Title"
@@ -14,7 +14,8 @@
                          Variant="Variant.Outlined"
                          Required="true"
                          RequiredError="Title is required"
-                         MaxLength="200" />
+                         MaxLength="200"
+                         ReadOnly="@IsPageNote" />
 
             <MudText Typo="Typo.subtitle2" Class="mb-2">Content (Markdown)</MudText>
             <MarkdownEditor Value="@_note.Content"
@@ -42,6 +43,8 @@
 
     private Note _note = null!;
 
+    private bool IsPageNote => Note?.Title?.StartsWith("@") ?? false;
+
     protected override void OnInitialized()
     {
         _note = new Note