feat(p1): add daily snapshots and fan tracking

Implement P1: seven-metric view snapshots, relation/stat fan snapshots, failure placeholders, resume by daily completion markers, Cookie login warnings, daily SQLite backups, Shanghai daily scheduling, and CLI snapshot/auth-check commands. Real read-only run captured 795/795 videos successfully over 1124s with a verified daily backup.

tests/test_maintenance.py

@@ -0,0 +1,78 @@
+# -*- coding: utf-8 -*-
+"""每日备份与保留期测试: uv run python tests/test_maintenance.py"""
+
+import os
+import sqlite3
+import sys
+import tempfile
+from pathlib import Path
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+sys.stdout.reconfigure(encoding="utf-8")
+
+from reaction_board.database import Database  # noqa: E402
+from reaction_board.services.maintenance import (  # noqa: E402
+    backup_daily,
+    daily_backup_path,
+    prune_daily_backups,
+)
+
+
+def test_daily_backup_and_restore():
+    with tempfile.TemporaryDirectory() as tmp:
+        db = Database(Path(tmp) / "app.db")
+        db.initialize()
+        try:
+            db.write(lambda c: c.execute("INSERT INTO kv(k, v) VALUES ('x', '42')"))
+            target = backup_daily(db, Path(tmp) / "backup", "2026-10-31")
+            assert target == daily_backup_path(Path(tmp) / "backup", "2026-10-31")
+            assert target.name == "app-20261031.db"
+            assert target.exists()
+
+            check = sqlite3.connect(target)
+            try:
+                assert check.execute("SELECT v FROM kv WHERE k='x'").fetchone()[0] == "42"
+            finally:
+                check.close()
+
+            # 覆盖同日备份也安全
+            db.write(lambda c: c.execute("UPDATE kv SET v='43' WHERE k='x'"))
+            backup_daily(db, Path(tmp) / "backup", "2026-10-31")
+            check = sqlite3.connect(target)
+            try:
+                assert check.execute("SELECT v FROM kv WHERE k='x'").fetchone()[0] == "43"
+            finally:
+                check.close()
+        finally:
+            db.close()
+
+
+def test_prune_daily_backups_only():
+    with tempfile.TemporaryDirectory() as tmp:
+        backup_dir = Path(tmp)
+        old_daily = backup_dir / "app-20260101.db"
+        fresh_daily = backup_dir / "app-20261031.db"
+        old_migration = backup_dir / "app-pre-v1-20260101.db"
+        other = backup_dir / "keep.txt"
+        for path in (old_daily, fresh_daily, old_migration, other):
+            path.write_bytes(b"x")
+        now = 1_800_000_000
+        old_time = now - 20 * 86400
+        for path in (old_daily, old_migration):
+            os.utime(path, (old_time, old_time))
+        os.utime(fresh_daily, (now, now))
+        removed = prune_daily_backups(backup_dir, keep_days=14, now=now)
+        assert removed == [old_daily]
+        assert fresh_daily.exists()
+        assert old_migration.exists()  # 迁移备份不属于日备份清理范围
+        assert other.exists()
+
+
+def main():
+    test_daily_backup_and_restore()
+    test_prune_daily_backups_only()
+    print("OK: 每日备份与保留期测试全部通过")
+
+
+if __name__ == "__main__":
+    main()