docs(gaps): record the engine review as gaps 33–44

[mo4islona]

What

spec/GAPS.md rewritten from a review of this engine against the reference.
make spec-check is clean; no other file changes.

• Gaps 33–44 in the register's own format (invariant, severity, reproduction,
  first test). Three S1: the budget early-stop on block-sorted tables drops whole
  blocks and moves lastBlock past them, thread-count dependent (33); a filter on
  a column stored at a physical type outside the predicate's downcast matrix
  matches nothing (40); roll fields tolerate absent source columns (41). Gaps 40
  and 41 need a chunk of an older archiver vintage to reach, so their rating is
  conditional and the register says so. One S2: the catalogs lag the reference by
  thirteen fields, and transactionConfig cannot be expressed without struct
  member encodings (35). Four S3 and three S4, including the relation path
  materialising every target before the budget (36).
• Deliberate-divergences table gains the rows the review found undocumented —
  malformed hex in a list, null filter values, the hyperliquidReplicaCmds
  alias predicates, shapes the reference rejects and this engine accepts. Two
  stale rows removed.
• "Outside the engine" — what the suite actually proves, and the three matrix
  rows that overstate their evidence.

How it was checked

Both engines run side by side over the real EVM and Solana chunks, every fixture
chunk and ~70 synthetic chunk variants; ~330 request probes, ~700 response and
pagination runs, peak-memory measurements, and the full request/field surface
diffed against the reference's macros. Every number in the file was produced by a
run on this branch's tree; the scratch harnesses are not part of the change.

What this does not do

It records; it decides nothing. Whether malformed-hex and null-filter strictness
holds during the migration, and whether three matrix rows drop from C to P,
are left as open questions in the text.

Findings about the seams outside this engine — deployment, distribution and
routing — are tracked privately and are not in this file.