fix(tui): show [0/0] instead of [1/0] for empty files

crates/tui/src/ui.rs

@@ -15,7 +15,12 @@ pub fn render(frame: &mut ratatui::Frame, app: &mut App) {
     // ── Title bar ──────────────────────────────────────────────────
     let title_text = if app.is_loaded() {
         let name = app.file_name().unwrap_or("unknown");
-        format!(" {} [{}/{}]", name, app.cursor_line + 1, app.total_lines())
+        let cursor_display = if app.total_lines() == 0 {
+            0
+        } else {
+            app.cursor_line + 1
+        };
+        format!(" {} [{}/{}]", name, cursor_display, app.total_lines())
     } else {
         " Log Viewer".to_string()
     };