feat: add terminal broadcast, context menu, and shell close

Complete multi-pane broadcast, standard terminal right-click actions, batch host selection with progress, and native ssh_close_shell so closing a pane tears down the remote shell.

Co-authored-by: Cursor <cursoragent@cursor.com>

src-tauri/src/services/ssh.rs

@@ -212,6 +212,19 @@ impl SshService {
             .map_err(|error| format!("调整远程终端尺寸失败: {error}"))
     }
 
+    pub fn close_shell(&self, shell_id: &str) -> Result<(), String> {
+        let mut shell = self
+            .shells
+            .lock()
+            .map_err(lock_error)?
+            .remove(shell_id)
+            .ok_or_else(|| format!("远程 Shell 不存在: {shell_id}"))?;
+        let _ = shell.channel.send_eof();
+        let _ = shell.channel.close();
+        let _ = shell.session.disconnect(None, "shell closed by user", None);
+        Ok(())
+    }
+
     pub fn forward_local(
         &self,
         connection_id: &str,