Eight MemoryConfig fields (float16, compression, compression_level,
compact_threshold, hebbian_boost, decay_factor, wal_enabled, wal_max_entries)
were never written to /meta, so reopening a store silently reset them to
defaults — a compressed store was rewritten uncompressed by the first
checkpoint after a reopen, and wal_enabled=false flipped back to true. They
are now stored as /meta attributes; each is optional on load so older files
keep opening with the previous defaults, and non-finite floats are ignored.
Writing the round-trip test exposed that `compression = true` never worked in
a default build: the embeddings dataset called with_zstd() unconditionally but
the agent crate never enabled the zstd feature, so every checkpoint failed
with "unsupported filter: 32015". The default build now compresses with
deflate (always available, pure Rust path); Zstd is opt-in via a new `zstd`
agent feature.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
