Prepare 0.1.0 for crates.io publish

Add dual MIT/Apache-2.0 license files and a crates.io README.
Bump dependencies to current: rand 0.8->0.10, aes-gcm 0.10->0.11,
base64 0.22->0.23. Add keywords, categories, readme, rust-version
fields to Cargo.toml. Migrate encryption.rs and test_vectors.rs to
the new rand/aes-gcm/base64 APIs.

Cargo.toml

@@ -2,9 +2,13 @@
 name = "alkvault"
 version = "0.1.0"
 edition = "2021"
+rust-version = "1.85"
 license = "MIT OR Apache-2.0"
 description = "Local key vault: BIP39 mnemonic generation, SLIP-0010 Ed25519 HD key derivation, AES-256-GCM encryption for securing provider keys, credentials, and identity material"
 repository = "https://git.alk.dev/alkdev/alkvault"
+readme = "README.md"
+keywords = ["vault", "bip39", "ed25519", "slip-0010", "encryption"]
+categories = ["cryptography", "authentication"]
 
 [lib]
 name = "alkvault"
@@ -16,15 +20,15 @@ secp256k1 = ["dep:secp256k1"]
 [dependencies]
 bip39 = { version = "2", features = ["rand", "zeroize"] }
 ed25519-bip32 = "0.4"
-aes-gcm = "0.10"
+aes-gcm = "0.11"
 sha2 = "0.10"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 thiserror = "2"
 zeroize = { version = "1", features = ["derive"] }
 hmac = "0.12"
-rand = "0.8"
-base64 = "0.22"
+rand = { version = "0.10", default-features = false, features = ["sys_rng"] }
+base64 = "0.23"
 secp256k1 = { version = "0.29", optional = true }
 
 [dev-dependencies]