ColumnStore silently skipped a manifest-listed segment it could not load: a
corrupt or missing segment dropped every one of its entities out of
filter/rangeQuery/sortTopK with no error, so an inconsistent index read as a
merely short result. It now throws a typed ColumnSegmentLoadError when a listed
segment yields undecodable or no bytes, and lets a genuine storage IO fault
propagate verbatim. Only a field with no manifest at all stays benign (nothing
was ever written for it).
baseStorage.getNoun_internal / getVerb_internal likewise caught every error and
returned null, reporting a present-but-unreadable entity as "not found". They
now return null only for genuine ENOENT-class absence (via isAbsentError) and
rethrow real faults and deserialize errors.
Pattern-B (blind catch) hardening: absence -> null, fault -> loud.