- Add TestWriteStoppedAfterIOError verifying ErrCommitUnknown → write-stopped
transition after I/O failure (DoD requirement)
- Replace VKValueLogPointer with VKInline in segment_writer_test.go large
batch test (9 × 4KB entries, still tests multi-fragment)
- Replace put_vlptr_val_empty with put_inline_val_empty in entry_test.go
- VKValueLogPointer remains only in constants_test.go (enum value check)
- wal/block_writer.go: 32KB block buffer with padding and flush
- wal/segment_writer.go: WAL segment file with durable-ready protocol
- memtable/memtable.go: Arena+SkipList wrapper with publish/abort semantics
- Comprehensive tests for all modules, all pass with -race
dailz