v0.5.0: Add syslog support, fix TCP send/both, EC-SRP5 server auth

New features:
- --syslog <address:port> sends structured events to remote syslog (RFC 5424 UDP)
  Events: AUTH_SUCCESS, AUTH_FAILURE, TEST_START, TEST_END, TEST_RESULT
- EC-SRP5 authentication for both client and server modes
- TCP multi-connection support (session tokens, all 3 directions)

Bug fixes since v0.2.0:
- EC-SRP5 server: fixed gamma parity (was 50% auth failure rate)
- EC-SRP5 server: use lift_x not redp1 for verification
- TCP send direction: server sends 12-byte status messages to client
- TCP both direction: TX loop injects status between data packets
- TCP data: send all zeros (no 0x07 header that MikroTik rejected)
- TCP disconnect detection: running flag set on EOF
- UDP multi-connection: unconnected socket accepts all source ports

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

src/lib.rs

@@ -4,3 +4,4 @@ pub mod client;
 pub mod ecsrp5;
 pub mod protocol;
 pub mod server;
+pub mod syslog_logger;