FuzzNewManifestFromReader fails when the parser returns both or neither
of a manifest and an error, or allocates more than sixteen times its
input plus MaxDecompressedSize. make test runs the committed seed
corpus; make fuzz fuzzes for one minute, by hand only.
Parser bug: MaxDecompressedSize did not bound decompression. The zstd
decoder kept its own 64 GiB limit, set aside whatever size a frame
header claimed, and decoded payloads under 128 KiB in full before the
LimitReader read any of it, so a 92-byte manifest claiming 8 GiB made
the parser allocate 8 GiB. The decoder now has MaxDecompressedSize as
its limit; that manifest is a regression seed.
Model: opus-5-5
