docs: document session preparation flow

packages/session-persistence/session-persistence-sqlite/README.md

@@ -21,7 +21,7 @@ On filesystems with POSIX modes, the backend requests mode `0700` for missing di
 - **Append = a transaction.** `append` runs `BEGIN`/`COMMIT` around the batch: it materializes the `sessions` row (if still lazy) and INSERTs every event, asserting the contiguous-seq contract first (the first event's `seq` must equal the stored next-seq). A mid-batch failure (a UNIQUE violation on a duplicated seq) rolls back entirely, so the stored log and the in-memory cursor stay consistent. (`load()` already balanced the stored log, so `append` never has to repair a crash tail.)
 - **Lazy materialization.** `create()` records intent in memory only — no row is written until the first `append`. A created-but-never-appended session has no `sessions` row, so it is absent from `list()` (which reports exactly the sessions that have a row).
 - **Interrupted-turn close on load.** `load()` implements the shared [crash-recovery contract](../../../.agents/notes/implemented/architecture/2026-06-14-session-persistence.md): preserve the valid interrupted turn, append its synthetic closing events in one transaction, and remove only a torn tail row. Committed parse errors or sequence gaps make the session unloadable. Because recovery mutates stored rows, the next append starts from a balanced log and accurate cursor.
-- **Non-mutating inspection.** `inspect()` returns the detached valid row prefix without deleting a torn tail row or appending recovery closers, and leaves the lightweight revision unchanged.
+- **Non-mutating inspection.** `inspect()` returns an immutable balanced logical view and may synthesize recovery closers in memory, without deleting a torn tail row, appending recovery rows, or changing the lightweight revision.
 - **Lightweight revisions.** `listSnapshots(signal?)` combines the immutable store and database-file identity, a per-materialization incarnation id, and a per-session counter incremented in each mutating transaction. This keeps unchanged observations stable without parsing event rows and distinguishes independent stores and recreated same-id logs. It checks cancellation before and after shared readiness and the synchronous metadata query; the query itself is non-preemptible.
 
 ## Configuration (schemastery)
@@ -30,6 +30,7 @@ On filesystems with POSIX modes, the backend requests mode `0700` for missing di
 interface Config {
   path: string   // SQLite database file path, or ':memory:' for an in-process DB
   journalMode?: 'wal' | 'delete' | 'truncate' | 'persist'   // journal_mode pragma; default 'wal'
+  preparedSessionCacheSize?: number   // positive integer; default 5
 }
 ```