Add app icons, screenshots, and complete AppStream metainfo

- Add GNOME HIG-compliant app icon (scalable SVG) and symbolic variant
- Add 12 screenshots covering all major views and features
- Flesh out metainfo with screenshots, categories, URLs, content
  rating, system requirements, provides, translation, donation
  and contact links
- Update AppImage build script to bundle GTK plugin, symbolic
  icon, and metainfo
- Update meson.build with icon installation rules
- Remove About dialog from application menu
- Remove unused user guide and audit tool

CONTRIBUTING.md

@@ -0,0 +1,137 @@
+# Contributing to Driftwood
+
+## Building from source
+
+### Dependencies
+
+- Rust 1.75+ and Cargo
+- GTK 4.16+ development headers (`libgtk-4-dev` or `gtk4-devel`)
+- libadwaita 1.6+ development headers (`libadwaita-1-dev` or `libadwaita-devel`)
+- SQLite 3 development headers
+- gettext development headers
+- `glib-compile-resources` and `glib-compile-schemas` (from `libglib2.0-dev-bin`)
+
+### Quick start
+
+```sh
+git clone https://github.com/driftwood-app/driftwood
+cd driftwood
+cargo build
+cargo run
+```
+
+### Running tests
+
+```sh
+cargo test
+```
+
+## Project structure
+
+```
+driftwood/
+  Cargo.toml               # Rust package manifest
+  build.rs                  # GResource and GSettings compilation
+  meson.build               # Meson build system for installation
+
+  src/
+    main.rs                 # Entry point, GResource init, CLI dispatch
+    application.rs          # GtkApplication subclass, CSS loading, app actions
+    window.rs               # Main window, navigation, scanning orchestration
+    config.rs               # App ID and version constants
+    cli.rs                  # Command-line interface (clap)
+    i18n.rs                 # Internationalization (gettext wrappers)
+
+    core/                   # Backend logic (no GTK dependencies)
+      database.rs           # SQLite database (rusqlite), all queries
+      discovery.rs          # Filesystem scanning, AppImage detection, SHA256
+      inspector.rs          # AppImage metadata extraction (icon, desktop entry)
+      integrator.rs         # Desktop integration (.desktop files, icons)
+      launcher.rs           # AppImage launching with FUSE/sandbox support
+      updater.rs            # Update checking and applying (GitHub, zsync)
+      fuse.rs               # FUSE status detection
+      wayland.rs            # Wayland compatibility analysis
+      security.rs           # CVE scanning via OSV.dev API
+      duplicates.rs         # Duplicate and multi-version detection
+      footprint.rs          # Disk footprint analysis (config/data/cache)
+      orphan.rs             # Orphaned desktop entry detection and cleanup
+
+    ui/                     # GTK4/libadwaita UI components
+      library_view.rs       # Main grid/list view of AppImages
+      app_card.rs           # Individual AppImage card widget
+      detail_view.rs        # Full detail page for a single AppImage
+      dashboard.rs          # System health dashboard
+      preferences.rs        # Preferences dialog
+      update_dialog.rs      # Update check and apply dialog
+      duplicate_dialog.rs   # Duplicate resolution dialog
+      cleanup_wizard.rs     # Disk space reclamation wizard
+      security_report.rs    # Security scan results view
+      integration_dialog.rs # Desktop integration confirmation
+      widgets.rs            # Shared utility widgets (badges, sections)
+
+  data/
+    app.driftwood.Driftwood.gschema.xml   # GSettings schema
+    app.driftwood.Driftwood.desktop       # Desktop entry for Driftwood itself
+    app.driftwood.Driftwood.metainfo.xml  # AppStream metadata
+    resources.gresource.xml               # GResource manifest
+    resources/style.css                   # Application CSS
+
+  po/                       # Translation files
+    POTFILES.in             # Files with translatable strings
+    LINGUAS                 # Available translations
+
+  build-aux/                # Build helpers
+    app.driftwood.Driftwood.json  # Flatpak manifest
+    build-appimage.sh             # AppImage build script
+
+  packaging/
+    PKGBUILD                # Arch Linux AUR package
+```
+
+## Architecture
+
+The codebase is split into three layers:
+
+1. **core/** - Pure Rust business logic. No GTK dependencies. Can be tested
+   independently. Each module handles one concern.
+
+2. **ui/** - GTK4/libadwaita widgets. Each view is a function that builds a
+   widget tree. Uses `Rc<Database>` for shared database access.
+
+3. **window.rs / application.rs** - Orchestration layer. Connects UI to core,
+   handles navigation, spawns background threads for scanning.
+
+Background work (scanning, update checks, security scans) runs on
+`gio::spawn_blocking` threads. Results are sent back to the main thread
+via `glib::spawn_future_local`.
+
+## Coding conventions
+
+- Follow standard Rust formatting (`cargo fmt`)
+- All new code must compile with zero warnings
+- Add tests for core/ modules (81+ tests currently)
+- Use `log::info!`, `log::warn!`, `log::error!` for diagnostics
+- User-facing strings should be wrapped in `i18n()` for translation
+- Use `adw::` widgets over raw `gtk::` when an Adwaita equivalent exists
+- Status badges use CSS classes: `badge-success`, `badge-warning`, `badge-error`
+
+## Database
+
+SQLite database stored at `~/.local/share/driftwood/driftwood.db`. Schema
+migrates automatically (v1 through v4). All queries are in `core/database.rs`.
+
+## Testing
+
+```sh
+# Run all tests
+cargo test
+
+# Run tests for a specific module
+cargo test core::database
+cargo test core::updater
+
+# Run with output
+cargo test -- --nocapture
+```
+
+Tests use `Database::open_in_memory()` for isolation.

data/app.driftwood.Driftwood.policy

@@ -5,7 +5,7 @@
 <policyconfig>
 
   <vendor>Driftwood</vendor>
-  <vendor_url>https://git.lashman.live/lashman/driftwood</vendor_url>
+  <vendor_url>https://github.com/driftwood-appimage</vendor_url>
 
   <action id="app.driftwood.Driftwood.system-install">
     <description>Install AppImage system-wide</description>

packaging/PKGBUILD

@@ -5,8 +5,8 @@ pkgver=0.1.0
 pkgrel=1
 pkgdesc='Modern AppImage manager for GNOME desktops'
 arch=('x86_64')
-url='https://git.lashman.live/lashman/driftwood'
-license=('CC0-1.0')
+url='https://github.com/driftwood-app/driftwood'
+license=('GPL-3.0-or-later')
 depends=(
     'gtk4'
     'libadwaita'

src/core/database.rs

@@ -51,7 +51,7 @@ pub struct AppImageRecord {
     pub tags: Option<String>,
     pub pinned: bool,
     pub avg_startup_ms: Option<i64>,
-    // Phase 9 fields - extended metadata
+    // Phase 9 fields - comprehensive metadata
     pub appstream_id: Option<String>,
     pub appstream_description: Option<String>,
     pub generic_name: Option<String>,