Wire remaining UI elements: presets, drag-drop, import/save, output summary

- Workflow preset cards now apply their config to JobConfig on selection
- User presets section shows saved custom presets from PresetStore
- Import Preset button opens file dialog and imports JSON presets
- Save as Preset button in results page saves current workflow
- Images step supports drag-and-drop for image files
- Images loaded state shows file list and clear button
- Output step dynamically shows operation summary when navigated to
- Output step wires preserve directory structure and overwrite behavior
- Results page displays individual error details in expandable section
- Pause button toggles visual state on processing page

pixstrip-gtk/src/steps/step_workflow.rs

@@ -1,7 +1,9 @@
 use adw::prelude::*;
 use pixstrip_core::preset::Preset;
+use pixstrip_core::operations::*;
+use crate::app::{AppState, JobConfig, MetadataMode};
 
-pub fn build_workflow_page() -> adw::NavigationPage {
+pub fn build_workflow_page(state: &AppState) -> adw::NavigationPage {
     let scrolled = gtk::ScrolledWindow::builder()
         .hscrollbar_policy(gtk::PolicyType::Never)
         .vexpand(true)
@@ -31,15 +33,23 @@ pub fn build_workflow_page() -> adw::NavigationPage {
         .homogeneous(true)
         .build();
 
-    for preset in Preset::all_builtins() {
-        let card = build_preset_card(&preset);
+    let builtins = Preset::all_builtins();
+    for preset in &builtins {
+        let card = build_preset_card(preset);
         builtin_flow.append(&card);
     }
 
-    // When a preset card is activated, advance to the next step
-    builtin_flow.connect_child_activated(|flow, _child| {
-        flow.activate_action("win.next-step", None).ok();
-    });
+    // When a preset card is activated, apply it to JobConfig and advance
+    {
+        let jc = state.job_config.clone();
+        builtin_flow.connect_child_activated(move |flow, child| {
+            let idx = child.index() as usize;
+            if let Some(preset) = builtins.get(idx) {
+                apply_preset_to_config(&mut jc.borrow_mut(), preset);
+            }
+            flow.activate_action("win.next-step", None).ok();
+        });
+    }
 
     builtin_group.add(&builtin_flow);
     content.append(&builtin_group);
@@ -63,15 +73,42 @@ pub fn build_workflow_page() -> adw::NavigationPage {
     custom_group.add(&custom_flow);
     content.append(&custom_group);
 
-    // User presets section (initially empty)
+    // User presets section
     let user_group = adw::PreferencesGroup::builder()
         .title("Your Presets")
         .description("Import or save your own workflows")
         .build();
 
+    // Show saved user presets
+    let store = pixstrip_core::storage::PresetStore::new();
+    if let Ok(presets) = store.list() {
+        for preset in &presets {
+            if !preset.is_custom {
+                continue;
+            }
+            let row = adw::ActionRow::builder()
+                .title(&preset.name)
+                .subtitle(&preset.description)
+                .activatable(true)
+                .build();
+            row.add_prefix(&gtk::Image::from_icon_name(&preset.icon));
+            row.add_suffix(&gtk::Image::from_icon_name("go-next-symbolic"));
+
+            let jc = state.job_config.clone();
+            let p = preset.clone();
+            row.connect_activated(move |r| {
+                apply_preset_to_config(&mut jc.borrow_mut(), &p);
+                r.activate_action("win.next-step", None).ok();
+            });
+
+            user_group.add(&row);
+        }
+    }
+
     let import_button = gtk::Button::builder()
         .label("Import Preset")
         .icon_name("document-open-symbolic")
+        .action_name("win.import-preset")
         .build();
     import_button.add_css_class("flat");
     user_group.add(&import_button);
@@ -91,6 +128,101 @@ pub fn build_workflow_page() -> adw::NavigationPage {
         .build()
 }
 
+fn apply_preset_to_config(cfg: &mut JobConfig, preset: &Preset) {
+    // Resize
+    match &preset.resize {
+        Some(ResizeConfig::ByWidth(w)) => {
+            cfg.resize_enabled = true;
+            cfg.resize_width = *w;
+            cfg.resize_height = 0;
+            cfg.allow_upscale = false;
+        }
+        Some(ResizeConfig::ByHeight(h)) => {
+            cfg.resize_enabled = true;
+            cfg.resize_width = 0;
+            cfg.resize_height = *h;
+            cfg.allow_upscale = false;
+        }
+        Some(ResizeConfig::FitInBox { max, allow_upscale }) => {
+            cfg.resize_enabled = true;
+            cfg.resize_width = max.width;
+            cfg.resize_height = max.height;
+            cfg.allow_upscale = *allow_upscale;
+        }
+        Some(ResizeConfig::Exact(dims)) => {
+            cfg.resize_enabled = true;
+            cfg.resize_width = dims.width;
+            cfg.resize_height = dims.height;
+            cfg.allow_upscale = true;
+        }
+        None => {
+            cfg.resize_enabled = false;
+        }
+    }
+
+    // Convert
+    match &preset.convert {
+        Some(ConvertConfig::SingleFormat(fmt)) => {
+            cfg.convert_enabled = true;
+            cfg.convert_format = Some(*fmt);
+        }
+        Some(_) => {
+            cfg.convert_enabled = true;
+            cfg.convert_format = None;
+        }
+        None => {
+            cfg.convert_enabled = false;
+            cfg.convert_format = None;
+        }
+    }
+
+    // Compress
+    match &preset.compress {
+        Some(CompressConfig::Preset(q)) => {
+            cfg.compress_enabled = true;
+            cfg.quality_preset = *q;
+        }
+        Some(CompressConfig::Custom { jpeg_quality, png_level, webp_quality, .. }) => {
+            cfg.compress_enabled = true;
+            if let Some(jq) = jpeg_quality {
+                cfg.jpeg_quality = *jq;
+            }
+            if let Some(pl) = png_level {
+                cfg.png_level = *pl;
+            }
+            if let Some(wq) = webp_quality {
+                cfg.webp_quality = *wq as u8;
+            }
+        }
+        None => {
+            cfg.compress_enabled = false;
+        }
+    }
+
+    // Metadata
+    match &preset.metadata {
+        Some(MetadataConfig::StripAll) => {
+            cfg.metadata_enabled = true;
+            cfg.metadata_mode = MetadataMode::StripAll;
+        }
+        Some(MetadataConfig::Privacy) => {
+            cfg.metadata_enabled = true;
+            cfg.metadata_mode = MetadataMode::Privacy;
+        }
+        Some(MetadataConfig::KeepAll) => {
+            cfg.metadata_enabled = true;
+            cfg.metadata_mode = MetadataMode::KeepAll;
+        }
+        Some(MetadataConfig::Custom { .. }) => {
+            cfg.metadata_enabled = true;
+            cfg.metadata_mode = MetadataMode::StripAll;
+        }
+        None => {
+            cfg.metadata_enabled = false;
+        }
+    }
+}
+
 fn build_preset_card(preset: &Preset) -> gtk::Box {
     let card = gtk::Box::builder()
         .orientation(gtk::Orientation::Vertical)