Append-only WAL with CRC32-validated records, automatic segment rotation
at 128 MiB, background periodic fsync, and crash recovery by truncation
at the first corrupt or incomplete record.
Record format: type(1) | len(4) | payload | crc32c(4). Two payload
types: series (ref + labels) and samples (batch of ref/t/v). Fixed-width
encoding througout.
Torn-write harness truncates at every byte offset and asserts recovery
produces a valid prefix of the original sequnce, both single-segment and
multi-segment.
DESIGN.md, NOTICE.md, and README.md.
