[Christiansalles]

Summary

• buffer TCP bytes until complete CRLF-terminated response lines are available
• preserve coalesced response bytes and parse the complete GV, GF, GJ, GI, and SE response shapes
• frame the welcome and login prompts even when TCP splits or coalesces them
• apply one 30-second deadline per response and invalidate sockets after timeout, partial EOF, malformed data, oversized buffers, or unexpected pending bytes
• keep the existing public function and command method signatures unchanged

Fixes #8.

Scope

This change covers login and line-oriented command responses. The bulk image, file, job, and settings transfer parser is intentionally not redesigned here because that work is already being discussed in #11.

Tests

• python -m unittest discover -s tests -v — 23 tests passed
• python -m compileall -q src tests — passed
• git diff --check — passed
• python -m build — source distribution and wheel built successfully
• installed-wheel smoke test with a fragmented GV response — passed