Read bounded embedding metadata through the mtime-keyed cache. Raw discovery
and each expected-root/full-class result use distinct composite keys, so a
foreign or diagnostic lookup cannot poison a later owning-root lookup.
Parameters
file: string
Absolute path to a .embed.db file.
OptionalexpectedVaultRoot: string
Optional exact root plus full-class filter; omit
for raw bounded diagnostics.
Returns Promise<PeekEmbedDbMetaResult>
Cached bounded metadata when class/root-compatible, null otherwise.
Read bounded embedding metadata through the mtime-keyed cache. Raw discovery and each expected-root/full-class result use distinct composite keys, so a foreign or diagnostic lookup cannot poison a later owning-root lookup.