Ports app/.../TranscriptCache.kt (chunked JSONL directory, suffix/gap
tracking, backwards line reader, damage recovery, eviction) with the
full TranscriptCacheTest suite (18 cases). One correction the port
found in translation: SessionCache::guard's Err branch would have
disabled the whole cache on a single damaged chunk, since a damaged
suffix and a real I/O failure both arrived as Err from the same
closure -- separated so damage discards only the one session, matching
the Kotlin original's separate `catch (e: Damaged)` from
`catch (e: IOException)`.
cargo test (67 passed), clippy --all-targets and fmt clean.
Co-Authored-By: Claude Sonnet <noreply@anthropic.com>
irisandClaude Fable 5.1