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-core/src/error.rs

@@ -11,7 +11,7 @@ pub enum Error {
     Proton(#[from] proton_sdk::ProtonError),
 
     #[error("keyring: {0}")]
-    Keyring(#[from] keyring::Error),
+    Keyring(#[from] keyring_core::Error),
 
     #[error("serialization: {0}")]
     Serde(#[from] serde_json::Error),