fix(ci): restore db safety smoke backup and sample-test skip behavior

scripts/ci_db_safety_smoke.py

@@ -9,6 +9,7 @@ from __future__ import annotations
 import argparse
 import json
 import os
+import sqlite3
 import subprocess
 import sys
 import tempfile
@@ -35,6 +36,16 @@ def parse_json_output(output: str) -> dict[str, Any]:
         return {"success": False, "error_code": "invalid_json_output"}
 
 
+def copy_sqlite_backup(source: Path, backup: Path) -> None:
+    """Create a standalone SQLite backup, including data still held in WAL."""
+    backup.parent.mkdir(parents=True, exist_ok=True)
+    if backup.exists():
+        backup.unlink()
+    with sqlite3.connect(f"file:{source}?mode=ro", uri=True) as source_conn:
+        with sqlite3.connect(backup) as backup_conn:
+            source_conn.backup(backup_conn)
+
+
 def main() -> int:
     args = parse_args()
     repo = Path(__file__).resolve().parents[1]
@@ -45,7 +56,7 @@ def main() -> int:
         target = tmp_path / "restored.sqlite3"
         try:
             fixture = create_ci_fixture_db(source)
-            backup.write_bytes(source.read_bytes())
+            copy_sqlite_backup(source, backup)
             if any(path.resolve() == DEFAULT_DB_PATH.resolve() for path in [source, backup, target]):
                 print(json.dumps({"success": False, "gate": "db-safety-smoke", "error_code": "operating_db_path_refused"}, ensure_ascii=False))
                 return 20