Implement NAPI connect() function — single SSH channel as duplex stream

- Add WraithConnectOptions struct with napi fields: server, peer, transport,
  identity (string path or Buffer), tlsServerName, insecure, irohRelay, proxy
- Add WraithStream napi class wrapping SSH channel read/write halves via
  ChannelStream::into_stream() + tokio::io::split()
- Implement connect() async function: transport creation (tcp, tls), SSH client
  connection, authenticate, open direct_tcpip channel, return WraithStream
- Identity field accepts file path (string) or in-memory key data (Buffer)
- All Rust errors marshalled to JavaScript exceptions with descriptive messages
- Add ForwardError enum to wraith-core (required by forward.rs)
- Enable tls, iroh features on wraith-core dependency
- 7 unit tests for key source resolution and address parsing

Cargo.lock

@@ -2395,6 +2395,7 @@ version = "3.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f1d395473824516f38dd1071a1a37bc57daa7be65b293ebba4ead5f7abb017a2"
 dependencies = [
+ "anyhow",
  "bitflags 2.11.1",
  "ctor",
  "futures",
@@ -2402,6 +2403,7 @@ dependencies = [
  "napi-sys",
  "nohash-hasher",
  "rustc-hash",
+ "tokio",
 ]
 
 [[package]]
@@ -5593,6 +5595,7 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "async-trait",
+ "futures",
  "ipnetwork",
  "iroh",
  "rand 0.10.1",
@@ -5620,6 +5623,8 @@ version = "0.1.0"
 dependencies = [
  "napi",
  "napi-derive",
+ "russh",
+ "tokio",
  "wraith-core",
 ]