fix(deps): restore filelock-lts dependency for Python 3.7-3.9

Author: 1minds3t

pyproject.toml

@@ -42,7 +42,8 @@ dependencies = [
     "typer>=0.4.0",
     "rich>=10.0.0",
 
-    # Filelock: vendored for <3.10, external for >=3.10 (CVE-2025-68146)
+    # Filelock: LTS backport for <3.10, official for >=3.10 (CVE-2025-68146)
+    "filelock-lts>=2025.68146; python_version < '3.10'",
     "filelock>=3.20.1; python_version >= '3.10'",
 
     # Packaging version splits - CRITICAL: pip-audit needs >=21.0 on ALL versions