Add Phase 5 enhancements: security, i18n, analysis, backup, notifications

- Database v8 migration: tags, pinned, avg_startup_ms columns
- Security scanning with CVE matching and batch scan
- Bundled library extraction and vulnerability reports
- Desktop notification system for security alerts
- Backup/restore system for AppImage configurations
- i18n framework with gettext support
- Runtime analysis and Wayland compatibility detection
- AppStream metadata and Flatpak-style build support
- File watcher module for live directory monitoring
- Preferences panel with GSettings integration
- CLI interface for headless operation
- Detail view: tabbed layout with ViewSwitcher in title bar,
  health score, sandbox controls, changelog links
- Library view: sort dropdown, context menu enhancements
- Dashboard: system status, disk usage, launch history
- Security report page with scan and export
- Packaging: meson build, PKGBUILD, metainfo

build-aux/app.driftwood.Driftwood.json

@@ -0,0 +1,43 @@
+{
+    "app-id": "app.driftwood.Driftwood",
+    "runtime": "org.gnome.Platform",
+    "runtime-version": "48",
+    "sdk": "org.gnome.Sdk",
+    "sdk-extensions": [
+        "org.freedesktop.Sdk.Extension.rust-stable"
+    ],
+    "command": "driftwood",
+    "finish-args": [
+        "--share=ipc",
+        "--socket=fallback-x11",
+        "--socket=wayland",
+        "--share=network",
+        "--filesystem=home:ro",
+        "--filesystem=xdg-data/applications:create",
+        "--filesystem=xdg-data/icons:create",
+        "--talk-name=org.freedesktop.DBus",
+        "--env=RUST_LOG=driftwood=info"
+    ],
+    "build-options": {
+        "append-path": "/usr/lib/sdk/rust-stable/bin",
+        "env": {
+            "CARGO_HOME": "/run/build/driftwood/cargo",
+            "RUST_BACKTRACE": "1"
+        }
+    },
+    "modules": [
+        {
+            "name": "driftwood",
+            "buildsystem": "meson",
+            "config-opts": [
+                "-Dbuildtype=release"
+            ],
+            "sources": [
+                {
+                    "type": "dir",
+                    "path": ".."
+                }
+            ]
+        }
+    ]
+}