Rewrite detail view copy for beginners, add tab transitions and lightbox fixes

- Replace technical jargon with plain language across all 4 detail tabs
- Friendly titles/subtitles with technical details available in tooltips
- Soften terminal commands ("Install with one command" instead of raw commands)
- Rename sections: Desktop Integration -> App Menu, Sandboxing -> App Isolation,
  Vulnerability Scanning -> Security Check, Capabilities -> Features
- Rewrite Wayland/FUSE explanations to avoid acronyms and dev terminology
- Update security report page with beginner-friendly descriptions
- Enable libadwaita 1.7 ViewStack crossfade transitions between detail tabs
- Rewrite screenshot lightbox as separate gtk::Window (fixes scroll jump on
  close, adds click-outside-to-close, rounded corners via CSS)
- Add prev/next navigation arrows and keyboard support to lightbox

Cargo.toml

@@ -6,7 +6,7 @@ license = "GPL-3.0-or-later"
 
 [dependencies]
 gtk = { version = "0.11", package = "gtk4", features = ["v4_16"] }
-adw = { version = "0.9", package = "libadwaita", features = ["v1_6"] }
+adw = { version = "0.9", package = "libadwaita", features = ["v1_7"] }
 glib = "0.22"
 gio = "0.22"