feat(persistence): PostgreSQL assistant store, chat persist fixes, gateway scripts

- Add SQLAlchemy Core repos, pg adapter/compat, assistant_store factory, Alembic bootstrap and migration/cutover scripts.

- Harden chat_message writes (NUL scrub for PG), turn_uuid on attempt failure, WS turn_runner fallbacks and gateway executed_turn_uuid init.

- start_gateway: log paths, PS7 stderr handling via cmd, background stdout/stderr redirect; runtime assistant_runtime_log_dir export.

- Ops: clear_all_chat_sessions with PG-only --postgresql and env-gated wipe; clear_postgres_chat_sessions.ps1.

- Tests: SA repos, pg compat, persist fallback, smoke env isolation; CI and docs touch-ups.

Co-authored-by: Cursor <cursoragent@cursor.com>

runtime/operations/scripts/assistant_import_sqlite_to_postgresql.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+# Import assistant SQLite (db_path) into PostgreSQL. Prerequisite: alembic upgrade head on target PG.
+#
+# Reads _local/system.env when present (--load-system-env). Target URL: AIA_ASSISTANT_DATABASE_URL
+# (or pass extra args, e.g. --pg-url 'postgresql+psycopg://...' --dry-run).
+#
+# Usage:
+#   chmod +x runtime/operations/scripts/assistant_import_sqlite_to_postgresql.sh
+#   export AIA_ASSISTANT_DATABASE_URL='postgresql+psycopg://user:pass@host:5432/oclaw'
+#   ./runtime/operations/scripts/assistant_import_sqlite_to_postgresql.sh --dry-run
+#   ./runtime/operations/scripts/assistant_import_sqlite_to_postgresql.sh
+
+set -euo pipefail
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../.." && pwd)"
+cd "$ROOT"
+export PYTHONPATH="${ROOT}${PYTHONPATH:+:${PYTHONPATH}}"
+exec python "${ROOT}/runtime/operations/scripts/migrate_assistant_sqlite_to_postgresql.py" \
+  --load-system-env \
+  --sqlite-from-db-path \
+  "$@"