Only "nothing at the path" reads as an empty store; a zero-byte file is Undecodable in every
runtime; a dangling link is an I/O error. Errors name keys and schema ids only, never stored
values, and echo a header only in the cultcache.store.v<digits> shape. Single-file writes
report NotReplaced / ReplacedNotDurable / Rejected; an unlock failure after a successful write
no longer replaces the write's result.
Soul passes 1-3; batch 4 closes pass 3. Merged tree 9d9e76d4 verified on Yggdrasil: Rust
(cultcache, cultnet, cultmesh), cultcache-ts 44 including the four-runtime interop test,
cultnet-ts 198, cultcache-py 47, GameCult.Caching.Tests 346.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>