* volume: encode all offset bytes when makeupDiff replays a write
makeupDiff patched only bytes 8:12 of the index entry, so under the
5BytesOffset build the fifth byte kept the old offset's high bits and the
replayed needle's index pointed 32 GiB-aligned ranges away from its body.
A later vacuum then dropped the entry as unreadable. Rebuild the entry with
needle_map.ToBytes, the same encoder the tombstone branch just below uses.
* volume: test makeupDiff replay across a 32 GiB offset boundary
Sparse-file test: truncate the .dat to 64 GiB after one write, compact,
write a second needle, commit, and assert the index offset matches the
.compacted size and the needle stays readable through a second vacuum.
Only runs under -tags=5BytesOffset.
Chris Lu
e2608edda4