fix(session-persistence): address permission review

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

@@ -8,7 +8,7 @@ A SQLite durable session-persistence backend — a second `SessionPersistence` i
 
 Each `SessionEvent` maps 1:1 onto a row in an `events` table `(session_id, seq, type, time, data, source_event_seqs, surface_op)` — `data` is the event payload as JSON text, so the row shape is the event verbatim (including `assistant/chunk`, keeping `seq` contiguous). The two `TEXT` columns `source_event_seqs` and `surface_op` are nullable; they store the event's optional surface-metadata fields (see [session surface](../../../docs/rfc/implemented/architecture/2026-06-18-session-surface.md)). Out-of-log metadata (`SessionHeader`) lives in a `sessions` row. A `sessions` row is written only by the first `append` — its existence is the lazy-materialization signal (`list` reports exactly the sessions that have a row), so no separate column is needed.
 
-The repository's Node range supports unflagged `node:sqlite`. The database enables foreign keys and uses the configured journal mode (`wal` by default; use a rollback mode where WAL shared-memory files are unsuitable). On filesystems with POSIX modes, missing directories are created as `0700` and a missing database is exclusively created as `0600` before SQLite opens it, causing new WAL sidecars to inherit owner-only access. Existing directories, database files, and sidecars keep their modes; ordinary filesystem access errors still fail initialization. `PRAGMA user_version` stores the table-layout version; databases with any other version are rejected because this unreleased format has no migrations.
+The repository's Node range supports unflagged `node:sqlite`. The database enables foreign keys and uses the configured journal mode (`wal` by default; use a rollback mode where WAL shared-memory files are unsuitable). On filesystems with POSIX modes, missing directories are created as `0700` and a missing database is exclusively created as `0600` before SQLite opens it, causing new WAL sidecars to inherit owner-only access. Existing directories, database files, and sidecars keep their modes; ordinary filesystem access errors still fail initialization. This default prevents incidental exposure through the process umask; it does not protect database integrity when another principal can modify entries in an existing parent directory. `PRAGMA user_version` stores the table-layout version; databases with any other version are rejected because this unreleased format has no migrations.
 
 ## Contract semantics over rows