refactor!: rebrand wraith to alknet

Rename all crates, CLI commands, constants, type names, doc comments,
and documentation from wraith to alknet. Includes wire-protocol changes:
ALPN wraith-ssh -> alknet-ssh, reserved destination prefix wraith- ->
alknet-, SSH auth username wraith -> alknet.

tasks/client/socks5-server.md

@@ -25,14 +25,14 @@ Supports SOCKS5h (domain names resolved server-side) by default. This prevents D
 
 ## Acceptance Criteria
 
-- [ ] `crates/wraith-core/src/socks5/mod.rs` exports `Socks5Server`
+- [ ] `crates/alknet-core/src/socks5/mod.rs` exports `Socks5Server`
 - [ ] `Socks5Server` binds to configurable listen address (default `127.0.0.1:1080`)
 - [ ] SOCKS5 handshake: method negotiation (no-auth only), target address parsing (IPv4, IPv6, domain name)
 - [ ] Domain name targets (SOCKS5h) sent unresolved to server — no local DNS resolution
 - [ ] For each SOCKS5 connection, opens SSH `direct_tcpip` channel and proxies bytes bidirectionally
 - [ ] Connection errors (SSH session down, channel open failed) result in SOCKS5 error response to client
 - [ ] No logging of SOCKS5 request targets (ADR-006) — only connection-level events logged
-- [ ] SOCKS5 server always enabled when `wraith connect` runs (per client.md constraint)
+- [ ] SOCKS5 server always enabled when `alknet connect` runs (per client.md constraint)
 - [ ] Unit tests: SOCKS5 handshake parsing, address type handling, bidirectional proxy flow (with mock transport)
 
 ## References