Add secure five-digit LAN pairing with automatic host discovery, encrypted credential handoff, polished host/client setup UI, persistence, tests, and documentation.

Hop-State: A_06FNQN729W1JAHZXV6PY1N0
Hop-Proposal: R_06FNQN68SGDZRN85WXQGSWG
Hop-Task: T_06FNQHGRCHN66DEC5171JF8
Hop-Attempt: AT_06FNQHGRCHPM6DR3BVFFMXG

src-tauri/Cargo.toml

@@ -13,9 +13,14 @@ crate-type = ["staticlib", "cdylib", "rlib"]
 tauri-build = { version = "2", features = [] }
 
 [dependencies]
+chacha20poly1305 = "0.10"
+getrandom = "0.3"
+hkdf = "0.12"
 keyring = "4.1"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+sha2 = "0.10"
+spake2 = { version = "0.4", features = ["getrandom"] }
 tauri = { version = "2", features = [] }
 tauri-plugin-dialog = "2"
 tauri-plugin-shell = "2"