Wire E2E messaging: send, recv, session persistence, auto-registration

CLI client (warzone):
- `warzone init` now generates pre-key bundle (1 SPK + 10 OTPKs),
  stores secrets in local sled DB, saves bundle for server registration
- `warzone register -s <url>` registers bundle with server
- `warzone send <fp> <msg> -s <url>` full E2E flow:
  - Auto-registers bundle on first use
  - Fetches recipient's pre-key bundle
  - Performs X3DH key exchange (first message) or uses existing session
  - Encrypts with Double Ratchet
  - Sends WireMessage envelope to server
- `warzone recv -s <url>` polls and decrypts:
  - Handles KeyExchange messages (X3DH respond + ratchet init as Bob)
  - Handles Message (decrypt with existing ratchet session)
  - Saves session state after each decrypt

Wire protocol (WireMessage enum):
- KeyExchange variant: sender identity, ephemeral key, OTPK id, ratchet msg
- Message variant: sender fingerprint + ratchet message

Session persistence:
- Ratchet state serialized with bincode, stored in sled (~/.warzone/db)
- Pre-key secrets stored in sled, OTPKs consumed on use
- Sessions keyed by peer fingerprint

Networking (net.rs):
- register_bundle, fetch_bundle, send_message, poll_messages
- JSON API over HTTP, bundles serialized with bincode + base64

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/crates/warzone-client/src/main.rs

@@ -15,7 +15,7 @@ struct Cli {
 
 #[derive(Subcommand)]
 enum Commands {
-    /// Generate a new identity (seed + keypair)
+    /// Generate a new identity (seed + keypair + pre-keys)
     Init,
     /// Recover identity from BIP39 mnemonic
     Recover {
@@ -25,6 +25,12 @@ enum Commands {
     },
     /// Show your fingerprint and public key
     Info,
+    /// Register your key bundle with a server
+    Register {
+        /// Server URL
+        #[arg(short, long, default_value = "http://localhost:7700")]
+        server: String,
+    },
     /// Send an encrypted message
     Send {
         /// Recipient fingerprint (e.g. a3f8:c912:44be:7d01)
@@ -49,22 +55,30 @@ enum Commands {
     },
 }
 
-fn main() -> anyhow::Result<()> {
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
     let cli = Cli::parse();
 
     match cli.command {
         Commands::Init => cli::init::run()?,
         Commands::Recover { words } => cli::recover::run(&words.join(" "))?,
         Commands::Info => cli::info::run()?,
+        Commands::Register { server } => {
+            cli::init::register_with_server(&server).await?;
+        }
         Commands::Send {
             recipient,
             message,
             server,
         } => {
-            println!("TODO: send '{}' to {} via {}", message, recipient, server);
+            // Auto-register bundle on first send
+            if let Err(_) = cli::init::register_with_server(&server).await {
+                eprintln!("Warning: failed to register bundle with server");
+            }
+            cli::send::run(&recipient, &message, &server).await?;
         }
         Commands::Recv { server } => {
-            println!("TODO: poll messages from {}", server);
+            cli::recv::run(&server).await?;
         }
         Commands::Chat { server } => {
             println!("TODO: launch TUI connected to {}", server);