Add database backups and automatic restore

Daemon job "backup" (online copy, quick_check, rotation), restore of the
newest valid copy when the database cannot be opened, change journal reset
after restore, last_restore in /health, docs and tests.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

collector_daemon.py

@@ -14,13 +14,27 @@ from apscheduler.schedulers.blocking import BlockingScheduler
 from apscheduler.triggers.cron import CronTrigger
 
 import cidr_collector as cc
+import db
 from cidr_collector import CIDRCollector, FQDNCollector, load_full_config
 from storage import StorageError, save_json_atomic, try_lock
 
 logger = logging.getLogger("collector_daemon")
 
-DEFAULT_CRONS = {"asn": "0 2 * * *", "fqdn": "0 3 * * *"}
-COLLECTORS = {"asn": CIDRCollector, "fqdn": FQDNCollector}
+DEFAULT_CRONS = {"asn": "0 2 * * *", "fqdn": "0 3 * * *", "backup": "30 4 * * *"}
+
+
+def run_backup():
+    """Задание backup: онлайн-копия базы, проверка, ротация (число копий - backup_keep в config.json)."""
+    keep = max(1, int(load_full_config().get("backup_keep", cc.DEFAULT_BACKUP_KEEP)))
+    with db.session() as conn:
+        path = db.backup_database(conn, datetime.datetime.now(), keep)
+    logger.info("Database backup written to %s (keeping the last %d)", path, keep)
+
+
+# Задания: имя -> вызываемый объект (новый экземпляр на каждый запуск - свежий config.json)
+COLLECTORS = {"asn": lambda: CIDRCollector().run_collection(),
+              "fqdn": lambda: FQDNCollector().run_collection(),
+              "backup": run_backup}
 LOCK_FILE = os.path.join(cc.DATA_DIR, "collector.daemon.lock")
 
 # Состояние заданий: действующий cron, результат последнего запуска, отклонённый cron (чтобы не спамить логом)
@@ -58,8 +72,7 @@ def run_job(name, scheduler):
         state["running"] = True
         write_status(scheduler)
         try:
-            # Новый экземпляр на каждый запуск - свежий config.json
-            COLLECTORS[name]().run_collection()
+            COLLECTORS[name]()
             state["last_error"] = None
         except Exception as e:
             logger.exception("%s collection failed", name)