Enhance history dialog with expandable details and DPI support

- History entries now use ExpanderRow with detailed sub-rows
- Show formatted timestamp, input/output directories, size breakdown
- Clickable output directory row opens file manager
- Per-entry undo and open folder action buttons
- Error count shown for batches with failures

pixstrip-gtk/src/app.rs

@@ -1151,12 +1151,69 @@ fn show_history_dialog(window: &adw::ApplicationWindow) {
                     .as_deref()
                     .unwrap_or("Custom workflow");
 
-                let row = adw::ActionRow::builder()
+                // Format timestamp
+                let time_label = entry.timestamp.parse::<u64>().ok().and_then(|ts| {
+                    let dt = glib::DateTime::from_unix_local(ts as i64).ok()?;
+                    let formatted = dt.format("%Y-%m-%d %H:%M").ok()?;
+                    Some(formatted.to_string())
+                }).unwrap_or_else(|| "Unknown date".to_string());
+
+                let row = adw::ExpanderRow::builder()
                     .title(preset_label)
-                    .subtitle(&subtitle)
+                    .subtitle(&format!("{} - {}", time_label, subtitle))
+                    .show_enable_switch(false)
                     .build();
                 row.add_prefix(&gtk::Image::from_icon_name("image-x-generic-symbolic"));
 
+                // Detail rows inside expander
+                let input_row = adw::ActionRow::builder()
+                    .title("Input")
+                    .subtitle(&entry.input_dir)
+                    .build();
+                input_row.add_prefix(&gtk::Image::from_icon_name("folder-symbolic"));
+                row.add_row(&input_row);
+
+                let output_row = adw::ActionRow::builder()
+                    .title("Output")
+                    .subtitle(&entry.output_dir)
+                    .activatable(true)
+                    .build();
+                output_row.add_prefix(&gtk::Image::from_icon_name("folder-open-symbolic"));
+                let out_dir = entry.output_dir.clone();
+                output_row.connect_activated(move |_| {
+                    let _ = gtk::gio::AppInfo::launch_default_for_uri(
+                        &format!("file://{}", out_dir),
+                        gtk::gio::AppLaunchContext::NONE,
+                    );
+                });
+                row.add_row(&output_row);
+
+                let size_row = adw::ActionRow::builder()
+                    .title("Size")
+                    .subtitle(&format!(
+                        "{} -> {} ({})",
+                        format_bytes(entry.total_input_bytes),
+                        format_bytes(entry.total_output_bytes),
+                        savings
+                    ))
+                    .build();
+                size_row.add_prefix(&gtk::Image::from_icon_name("drive-harddisk-symbolic"));
+                row.add_row(&size_row);
+
+                if entry.failed > 0 {
+                    let err_row = adw::ActionRow::builder()
+                        .title("Errors")
+                        .subtitle(&format!("{} files failed", entry.failed))
+                        .build();
+                    err_row.add_prefix(&gtk::Image::from_icon_name("dialog-warning-symbolic"));
+                    row.add_row(&err_row);
+                }
+
+                // Action buttons row
+                let actions_row = adw::ActionRow::builder()
+                    .title("Actions")
+                    .build();
+
                 // Undo button - moves output files to trash
                 if !entry.output_files.is_empty() {
                     let undo_btn = gtk::Button::builder()
@@ -1177,9 +1234,26 @@ fn show_history_dialog(window: &adw::ApplicationWindow) {
                         btn.set_sensitive(false);
                         btn.set_tooltip_text(Some(&format!("{} files moved to trash", trashed)));
                     });
-                    row.add_suffix(&undo_btn);
+                    actions_row.add_suffix(&undo_btn);
                 }
 
+                // Open output folder button
+                let open_btn = gtk::Button::builder()
+                    .icon_name("folder-open-symbolic")
+                    .tooltip_text("Open output folder")
+                    .valign(gtk::Align::Center)
+                    .build();
+                open_btn.add_css_class("flat");
+                let out_dir2 = entry.output_dir.clone();
+                open_btn.connect_clicked(move |_| {
+                    let _ = gtk::gio::AppInfo::launch_default_for_uri(
+                        &format!("file://{}", out_dir2),
+                        gtk::gio::AppLaunchContext::NONE,
+                    );
+                });
+                actions_row.add_suffix(&open_btn);
+
+                row.add_row(&actions_row);
                 group.add(&row);
             }
             content.append(&group);