- Added `IndexedSessionStorage` with `SessionStorageBackend` for index-based storage reads.
- Removed `readTextSync` from the public `SessionStorage` API and sync backends.
- Changed Redis and SQL backends to warm `{size, mtimeMs}` metadata and read via `readTextSlices`.
- Added per-path write queues and `drain()` to serialize operations and surface first failures.
- Classified each session's final message as done, interrupted, aborted, error, or pending from a 32 KiB tail read.
- Rendered the status as a colored segment on the session metadata line.
- Added `peekFileTail` and `readTextSuffix` across storage backends to read file tails in one pass.
- Simplified `MemorySessionStorage` to a string array mirror with a sidecar mtime map.
`SessionManager.close()` queues `#closePersistWriterInternal()` on the
persist chain. The task awaits `#persistWriter.close()`, which flips
`#closing = true` synchronously before yielding on its inner writer
`close()`. A concurrent `appendMessage()` landing in that yield window
hit the hot path, got the still-cached (but closing) writer back from
`#ensurePersistWriter()`, and threw `Error("Writer closed")` from
`writeSync`. The throw was stashed into `#persistError`; the next async
caller (`flush()` or a later `appendMessage()`) re-threw it as an
unhandled rejection with the original line-1282 stack.
Expose `NdjsonFileWriter.isOpen()` and treat a mid-close cached writer
as a miss in `#ensurePersistWriter()`. `_persist` now falls back to the
async `#rewriteFile()` cold path so the entry — already in
`#fileEntries` — still lands on disk once the close drains.
can1357