Use correct comparison in SACK reordering to avoid wrapping errors

[danielinux]

Found via fenrir/145

[Copilot]

Pull request overview

This PR fixes wrap-around bugs in TCP SACK block normalization by switching SACK block ordering/merging comparisons to use the stack’s wrap-aware TCP sequence comparison helpers, and adds regression tests to cover the wrap case.

Changes:

• Use tcp_seq_lt() in tcp_sort_sack_blocks() to sort SACK blocks with wrap-aware ordering.
• Use tcp_seq_lt() / tcp_seq_leq() in tcp_merge_sack_blocks() to merge ranges correctly when sequence numbers wrap.
• Add unit tests that validate sort/merge behavior across a wrap boundary and register them in the suite.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/wolfip.c	Updates SACK sort/merge logic to use wrap-aware TCP sequence comparisons to avoid incorrect ordering/merging near 32-bit wrap.
src/test/unit/unit.c	Adds and wires up unit tests that reproduce/guard the wrap-around ordering behavior for SACK sort/merge.

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[gasbytes]

confirmed locally as usual with gh pr checkout, lgtm.