BlobsBundle proof-count validation mismatch breaks Fulu blob tests

[0w3n-d]

Status

Three tests are currently broken on develop (discovered while re-enabling CI's unit-test job): bid_submission::tests::fulu_bid_submission, bid_submission::tests::fulu_bid_submission_ssz, blobs::tests::test_payload_and_blobs_equivalence (all in crates/types).

Why

BlobsBundle's SSZ decode validation (crates/types/src/blobs.rs) requires proofs.len() == blobs.len() * CELLS_PER_EXT_BLOB (256 cell-proofs per blob, Fulu's PeerDAS scheme). Two independent things violate this:

• BlobsBundle::random_for_test (crates/types/src/blobs.rs) pushes exactly one proof per blob instead of 256, so any test that round-trips a randomly generated bundle through SSZ fails deterministically.
• The committed fixture crates/types/src/testdata/signed-bid-submission-fulu.json itself only carries 1 proof per blob (2 proofs for 2 blobs) — looks like it predates the 256-proofs-per-blob requirement and needs regenerating, or the validation is stricter than it should be. Needs investigation to know which side is wrong.

Affected surface

• crates/types/src/blobs.rs — BlobsBundle::random_for_test
• crates/types/src/testdata/signed-bid-submission-fulu.json — stale fixture
• crates/types/src/bid_submission.rs, crates/types/src/blobs.rs — the 3 tests, currently marked #[ignore] pointing here

Steps

• Determine whether the fixture or the validation logic is authoritative for the 256-proofs-per-blob relationship
• Regenerate the fixture and/or fix random_for_test, whichever is wrong
• Un-ignore the 3 tests