fix: echo server TargetInfo in NTLMv2 AUTHENTICATE to fix STATUS_LOGON_FAILURE

[nima-sayadi]

Summary

NTLMv2 authentication fails against real SMB servers even with correct
credentials, returning STATUS_LOGON_FAILURE (0xC000006D) during session setup.
This affects Windows 10/11 and Samba-based NAS (e.g. AVM FritzBox).

Root cause

• decodeChallengeMessage returned only the 8-byte server challenge and threw
  away the server's TargetInfo (AV_PAIR list) from the CHALLENGE.
• encodeAuthenticationMessage therefore fabricated its own TargetInfo
  from the client hostname/domain. Per MS-NLMP, the NTLMv2 NTProofStr is an
  HMAC over (among other things) the server's TargetInfo, so a fabricated one
  makes the proof mismatch and the server rejects the logon.
• The AUTHENTICATE message also advertised negotiateFlags = 0 (stripping
  Unicode / extended session security) and, for unqualified users, hashed with
  an empty/guessed domain.

Fix

• decodeChallengeMessage now returns the full challenge: server challenge,
  raw TargetInfo, target name, and the parsed domain/timestamp.
• encodeAuthenticationMessage echoes the server's TargetInfo verbatim,
  derives the domain from the challenge when the caller supplies none, prefers
  the server-supplied timestamp, and advertises correct negotiate flags.
• createNtlmV2Response includes the trailing reserved field so the blob is
  byte-exact per MS-NLMP.
• Removed the fabricated-TargetInfo helper and the console.log handshake noise.

Testing

Added test/ntlm.test.ts (run with npm test) validating against the official
MS-NLMP 4.2.4 test vectors:

• NT hash, NTOWFv2, and the NTLMv2 NTProofStr (68cd0ab8…)
• CHALLENGE decoding (server challenge, target name, TargetInfo)

Verified end-to-end against a live FritzBox SMB share (previously failing with
STATUS_LOGON_FAILURE, now authenticates and performs file operations).

Notes

• decodeChallengeMessage now returns an object instead of a Buffer. The only
  in-repo caller (Session) is updated; external callers using it directly would
  need to read .serverChallenge.