chore(deps,core,gui): upgrade dependencies to latest

- keyring 3 -> keyring-core 1 + dbus-secret-service-keyring-store 1
  (crypto-rust). Same libdbus Secret Service backend; with no target the
  store matches items keyring 3 wrote, so stored sessions survive.
- ksni 0.2 -> 0.3 via the blocking API, with assume_sni_available so a
  tray that starts before the SNI watcher waits instead of failing. Drops
  the clap 2 / atty chain (Dependabot atty advisory).
- gtk4 0.11, libadwaita 0.9, webkit6 0.6, rusqlite 0.40, fuser 0.18,
  directories 6, sha1/sha2 0.11, base64 0.23.

crates/pdfs-gui/src/prompt.rs

@@ -1364,7 +1364,7 @@ fn icon_for(name: &str, is_dir: bool) -> gio::Icon {
     if is_dir {
         return gio::ThemedIcon::new("folder").upcast();
     }
-    let (content_type, _uncertain) = gio::functions::content_type_guess(Some(name), &[]);
+    let (content_type, _uncertain) = gio::functions::content_type_guess(Some(name), None);
     gio::functions::content_type_get_icon(&content_type)
 }