Add WCAG 2.2 AAA compliance and automated AT-SPI audit tool

- Bring all UI widgets to WCAG 2.2 AAA conformance across all views
- Add accessible labels, roles, descriptions, and announcements
- Bump focus outlines to 3px, target sizes to 44px AAA minimum
- Fix announce()/announce_result() to walk widget tree via parent()
- Add AT-SPI accessibility audit script (tools/a11y-audit.py) that
  checks SC 4.1.2, 1.1.1, 1.3.1, 2.1.1, 2.5.5, 2.5.8, 2.4.8,
  2.4.9, 2.4.10, 2.1.3 with JSON report output for CI
- Clean up project structure, archive old plan documents

src/ui/integration_dialog.rs

@@ -57,6 +57,7 @@ pub fn show_integration_dialog(
                     .pixel_size(32)
                     .build();
                 image.set_paintable(Some(&texture));
+                image.update_property(&[gtk::accessible::Property::Label(name)]);
                 name_row.add_prefix(&image);
             }
         }
@@ -88,6 +89,7 @@ pub fn show_integration_dialog(
         .build();
     let check1 = gtk::Image::from_icon_name("emblem-ok-symbolic");
     check1.set_valign(gtk::Align::Center);
+    check1.set_accessible_role(gtk::AccessibleRole::Presentation);
     desktop_row.add_prefix(&check1);
     actions_box.append(&desktop_row);
 
@@ -97,6 +99,7 @@ pub fn show_integration_dialog(
         .build();
     let check2 = gtk::Image::from_icon_name("emblem-ok-symbolic");
     check2.set_valign(gtk::Align::Center);
+    check2.set_accessible_role(gtk::AccessibleRole::Presentation);
     icon_row.add_prefix(&check2);
     actions_box.append(&icon_row);
 
@@ -156,6 +159,7 @@ pub fn show_integration_dialog(
             .build();
         let warning_icon = gtk::Image::from_icon_name("dialog-warning-symbolic");
         warning_icon.set_pixel_size(16);
+        warning_icon.set_accessible_role(gtk::AccessibleRole::Presentation);
         warning_header.append(&warning_icon);
         let warning_title = gtk::Label::builder()
             .label(&i18n("Compatibility Notes"))
@@ -168,6 +172,9 @@ pub fn show_integration_dialog(
         let compat_list = gtk::ListBox::new();
         compat_list.add_css_class("boxed-list");
         compat_list.set_selection_mode(gtk::SelectionMode::None);
+        compat_list.update_property(&[
+            gtk::accessible::Property::Label(&i18n("Compatibility warnings")),
+        ]);
 
         for (title, subtitle, badge_text) in &warnings {
             let row = adw::ActionRow::builder()