The Pass-1 hardening made loadBinaryBlob distinguish genuine absence (ENOENT →
null) from a real fault (EIO/EACCES/… → throw), so a present-but-unreadable blob
stops masquerading as "absent". The native column-store still has two call sites
that rely on the old null-on-error contract; publishing the throw ahead of them
would break a consumer running new brainy + old cortex.
Per the cortex coordination (accept: cor first, then brainy), this temporarily
restores the shipped 8.2.5 swallow-on-fault behavior for loadBinaryBlob ONLY, so
the rest of Pass 1 — saveBinaryBlob write-honesty, clear() native wipe,
pending-flush durability, count symmetry, degraded surfacing, aggregation
loudness — can release now. The method carries an inline restore guide; the
throwing form goes back in and ships lockstep with the native hardening. No other
Pass-1 change depends on this behavior (ColumnStore's own fault test uses a
direct-throwing storage stub), so the split is behaviour-neutral for every
consumer versus 8.2.5.