feat(clipboard): PASTESPEC pastes in a chosen format

PASTESPEC offers the formats on the clipboard: Objects and Block for
objects copied in the application (the PASTECLIP and PASTEBLOCK paths),
and Text for the system clipboard's text, placed as multi-line text in
the current text style with its lines as paragraphs.

Refs #645

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/commands/count.rs

@@ -188,7 +188,7 @@ impl OpenCADStudio {
         }
     }
 
-    fn start_count_command(&mut self, i: usize, command: Box<dyn CadCommand>) -> Task<Message> {
+    pub(in crate::app) fn start_count_command(&mut self, i: usize, command: Box<dyn CadCommand>) -> Task<Message> {
         self.reset_command_start_state(i);
         self.command_line.push_info(&command.prompt());
         self.tabs[i].active_cmd = Some(command);