fix(sftp): stop calling a filtered-out directory empty

Typing a filter that matched no entry left the remote Files panel saying
"Empty directory." — not silence, a false statement, and about a machine
the reader cannot see for themselves. It now says which query matched
nothing, the way the local file tree already does for the same case.

Not verified on screen: reaching this panel needs a live SSH host. The
branch is the one the local tree takes, and the full suite passes.

src/ui/sftp.rs

@@ -1245,8 +1245,13 @@ impl Tty7App {
         let show_go_up = self.sftp_panel.cwd != "/" && filter.trim().is_empty();
 
         if entries.is_empty() && !show_go_up {
+            // A filter that matched nothing is not an empty directory, and
+            // saying so about a machine you cannot see is worse than saying
+            // nothing. The local file tree already draws this distinction.
             let text: gpui::SharedString = if self.sftp_panel.loading {
                 t(L10nKey::SftpLoading).into()
+            } else if !filter.trim().is_empty() {
+                t_fmt(L10nKey::SettingsNothingMatches, &[("query", filter.trim())]).into()
             } else {
                 t(L10nKey::SftpEmptyDirectory).into()
             };