Implement Driftwood AppImage manager - Phases 1 and 2

Phase 1 - Application scaffolding:
- GTK4/libadwaita application window with AdwNavigationView
- GSettings-backed window state persistence
- GResource-compiled CSS and schema
- Library view with grid/list toggle, search, sorting, filtering
- Detail view with file info, desktop integration controls
- Preferences window with scan directories, theme, behavior settings
- CLI with list, scan, integrate, remove, clean, inspect commands
- AppImage discovery, metadata extraction, desktop integration
- Orphaned desktop entry detection and cleanup
- AppImage packaging script

Phase 2 - Intelligence layer:
- Database schema v2 with migration for status tracking columns
- FUSE detection engine (libfuse2/3, fusermount, /dev/fuse, AppImageLauncher)
- Wayland awareness engine (session type, toolkit detection, XWayland)
- Update info parsing from AppImage ELF sections (.upd_info)
- GitHub/GitLab Releases API integration for update checking
- Update download with progress tracking and atomic apply
- Launch wrapper with FUSE auto-detection and usage tracking
- Duplicate and multi-version detection with recommendations
- Dashboard with system health, library stats, disk usage
- Update check dialog (single and batch)
- Duplicate resolution dialog
- Status badges on library cards and detail view
- Extended CLI: status, check-updates, duplicates, launch commands

49 tests passing across all modules.

src/ui/app_card.rs

@@ -0,0 +1,119 @@
+use gtk::prelude::*;
+
+use crate::core::database::AppImageRecord;
+use crate::core::fuse::FuseStatus;
+use crate::core::wayland::WaylandStatus;
+use super::widgets;
+
+/// Build a grid card for an AppImage.
+pub fn build_app_card(record: &AppImageRecord) -> gtk::FlowBoxChild {
+    let card = gtk::Box::builder()
+        .orientation(gtk::Orientation::Vertical)
+        .spacing(6)
+        .margin_top(12)
+        .margin_bottom(12)
+        .margin_start(12)
+        .margin_end(12)
+        .halign(gtk::Align::Center)
+        .build();
+    card.add_css_class("app-card");
+    card.set_size_request(160, -1);
+
+    // Icon (48x48)
+    let icon = if let Some(ref icon_path) = record.icon_path {
+        let path = std::path::Path::new(icon_path);
+        if path.exists() {
+            let paintable = gtk::gdk::Texture::from_filename(path).ok();
+            let image = gtk::Image::builder()
+                .pixel_size(48)
+                .build();
+            if let Some(texture) = paintable {
+                image.set_paintable(Some(&texture));
+            } else {
+                image.set_icon_name(Some("application-x-executable-symbolic"));
+            }
+            image
+        } else {
+            gtk::Image::builder()
+                .icon_name("application-x-executable-symbolic")
+                .pixel_size(48)
+                .build()
+        }
+    } else {
+        gtk::Image::builder()
+            .icon_name("application-x-executable-symbolic")
+            .pixel_size(48)
+            .build()
+    };
+
+    // App name
+    let name = record.app_name.as_deref().unwrap_or(&record.filename);
+    let name_label = gtk::Label::builder()
+        .label(name)
+        .css_classes(["app-card-name"])
+        .ellipsize(gtk::pango::EllipsizeMode::End)
+        .max_width_chars(18)
+        .build();
+
+    // Version
+    let version_text = record.app_version.as_deref().unwrap_or("");
+    let version_label = gtk::Label::builder()
+        .label(version_text)
+        .css_classes(["app-card-version"])
+        .ellipsize(gtk::pango::EllipsizeMode::End)
+        .build();
+
+    card.append(&icon);
+    card.append(&name_label);
+    if !version_text.is_empty() {
+        card.append(&version_label);
+    }
+
+    // Status badges row
+    let badges = gtk::Box::builder()
+        .orientation(gtk::Orientation::Horizontal)
+        .spacing(4)
+        .halign(gtk::Align::Center)
+        .build();
+    badges.add_css_class("badge-row");
+
+    // Wayland status badge
+    if let Some(ref ws) = record.wayland_status {
+        let status = WaylandStatus::from_str(ws);
+        if status != WaylandStatus::Unknown {
+            badges.append(&widgets::status_badge(status.label(), status.badge_class()));
+        }
+    }
+
+    // FUSE status badge
+    if let Some(ref fs) = record.fuse_status {
+        let status = FuseStatus::from_str(fs);
+        if !status.is_functional() {
+            badges.append(&widgets::status_badge(status.label(), status.badge_class()));
+        }
+    }
+
+    // Update available badge
+    if record.latest_version.is_some() {
+        if let (Some(ref latest), Some(ref current)) =
+            (&record.latest_version, &record.app_version)
+        {
+            if crate::core::updater::version_is_newer(latest, current) {
+                badges.append(&widgets::status_badge("Update", "info"));
+            }
+        }
+    }
+
+    // Integration badge (only show if not integrated, to reduce clutter)
+    if !record.integrated {
+        badges.append(&widgets::status_badge("Not integrated", "neutral"));
+    }
+
+    card.append(&badges);
+
+    let child = gtk::FlowBoxChild::builder()
+        .child(&card)
+        .build();
+
+    child
+}