Phase 1 delivers the complete durability and storage layer:
- WAL with crash recovery: Append-only journal with BLAKE3 checksums,
fsync guarantees, and proper seek-to-EOF on reopen
- Storage engine: sled-backed KVStore with scan_prefix for range queries
- Content-addressed storage: H:{hash}, V:{hash}, E:{hash} key patterns
- Ingestor: Background worker tailing WAL, writing to KV with 8-byte
aligned record headers for rkyv zero-copy deserialization
- Comprehensive tests: 31 tests covering crash recovery, round-trips,
and multi-cycle durability
New crates: stemedb-wal, stemedb-storage, stemedb-ingest
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
