Implement embedded OpenPGP compatibility (#4)

Cargo.toml

@@ -20,6 +20,8 @@ clap = { version = "4.6", features = ["derive"] }
 crossterm = "0.29"
 iced = "0.14"
 ironstorage = { path = "crates/storage" }
+pgp = { version = "0.20", default-features = false }
+rand = "0.8"
 ratatui = { version = "0.30", default-features = false, features = ["crossterm_0_29", "layout-cache", "macros", "underline-color"] }
 serde = { version = "1", features = ["derive"] }
 shlex = "1.3"