Event-stream differential — Slice 2: extend to JSONTestSuite + LALR wild

[okalldal]

Part of #594. Follows Slice 1 (#595), which lands the generic tracer + event-stream
differential over the LALR compliance bank.

Context

Slice 1 establishes the machinery (grammar-agnostic tracer on both sides, event-stream
oracle, parse_into replay, XFAIL + freshness gates) over compliance/bank.json. This
slice points the same machinery at the two other LALR-drivable corpora so the whole
LALR suite runs through the event path.

Done-when

• The Slice 1 event-stream differential is extended to:
  • JSONTestSuite (293 inputs, JSON grammar under LALR) — accepted inputs replayed
    through parse_into with the event-logging builder, byte-identical to Python's
    embedded event stream.
  • LALR wild projects (tests/wild/, the projects whose upstream options use LALR —
    e.g. lark_lark, poetry_*, pyquil, tartiflette; excluding Earley/dynamic projects
    like mistql, which have no embedded oracle).
• Same XFAIL-burndown discipline and oracle-freshness gate as Slice 1 and the existing
  banks; no silent skips.
• Large event streams are digest-compared (mirror tests/test_wild.rs's big-tree
  digest handling) so the fixtures stay small.

Priority

prio:later — the compliance bank (Slice 1) already covers the bulk of grammar shapes;
this widens the corpus but is incremental once the machinery exists.

Files

• tools/generate_transformer_oracles.py / tools/generate_wild_oracles.py (event-stream
  emission for the two corpora)
• tests/fixtures/oracles/transformer/ + tests/fixtures/oracles/wild/ (event-stream
  fixtures / digests)
• tests/test_transform_event_stream.rs (extend the replay to the two corpora)

Notes

• Only LALR-config wild projects — an Earley/dynamic-lexer project has no embedded
  transformer oracle (Python restricts transformer= to LALR), so it is out of scope by
  construction, exactly as in Slice 1.
• JSONTestSuite's i_/n_ (implementation-defined / reject) inputs follow the same
  accepted-subset rule: only inputs Python accepts (and transforms) are differenced.