style!: adopt the core lint bar and migrate to it

The package carried no ruff configuration at all, so it ran on the defaults (E4+E7+E9+F) while infinito-nexus-core, its only consumer, holds itself to a far wider selection. Measured against that selection this tree had 224 findings. It now has none.

The selector list is core's verbatim so both repositories answer to one bar. target-version stays py39 rather than core's py311, because requires-python still declares >=3.9 and pyupgrade would otherwise propose syntax the declared minimum cannot run. Every ignore carries its reason: S603/S607 in particular, since running docker and dump binaries from PATH in list form is this tool's whole job and is already injection-safe.

Two conversions are judgement rather than mechanics. os.path.join(dir, '') was the rsync idiom for a trailing separator, which Path drops, so it becomes an explicit os.sep. os.path.abspath stays where Path.resolve() would follow symlinks and let a symlinked volume test as inside the snapshot subject.

BREAKING CHANGE: VersionMismatch is renamed VersionMismatchError.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/baudolo/restore/files.py

@@ -12,6 +12,7 @@ from __future__ import annotations
 
 import os
 import sys
+from pathlib import Path
 
 from .run import docker_volume_exists, run, stdout_of
 
@@ -21,7 +22,7 @@ INSPECT_FORMAT = (
 
 
 def restore_volume_files(volume_name: str, backup_files_dir: str) -> int:
-    if not os.path.isdir(backup_files_dir):
+    if not Path(backup_files_dir).is_dir():
         print(f"ERROR: backup files dir not found: {backup_files_dir}", file=sys.stderr)
         return 2
 
@@ -44,7 +45,7 @@ def restore_volume_files(volume_name: str, backup_files_dir: str) -> int:
         )
         return 2
 
-    driver, options = (fields + ["local", "plain"])[1:3]
+    driver, options = ([*fields, "local", "plain"])[1:3]
     if (driver != "local" or options == "opts") and not os.path.ismount(mountpoint):
         print(
             f"ERROR: volume {volume_name} has a backing store of its own "
@@ -55,8 +56,9 @@ def restore_volume_files(volume_name: str, backup_files_dir: str) -> int:
         )
         return 2
 
-    src = os.path.join(backup_files_dir, "")
-    dest = os.path.join(mountpoint, "")
+    # rsync reads "dir/" as its contents and "dir" as the directory itself.
+    src = f"{Path(backup_files_dir)}{os.sep}"
+    dest = f"{Path(mountpoint)}{os.sep}"
     run(["rsync", "-avv", "--delete", src, dest])
     print("File restore complete.")
     return 0