**Replace Flake8 with Ruff, refactor type hints, and enhance archive processing logic**

- Removed `flake8` and `flake8-annotations` from dependencies, replaced by `ruff` for linting.
- Introduced cleaner type hinting and modern Python annotations (PEP 604 style) across multiple modules.
- Moved archive processing to a dedicated helper (`comic.archives`) for improved maintainability.
- Updated and simplified logic for archive file retrieval, directory cleaning, and user access validation.
- Improved error handling and added support for user classification restrictions in API responses.

comic/archives.py

@@ -0,0 +1,30 @@
+"""Shared helpers for listing the pages inside a comic archive."""
+
+import mimetypes
+import zipfile
+from typing import NamedTuple
+
+import rarfile
+
+
+class ArchiveFile(NamedTuple):
+    file_name: str
+    mime_type: str
+
+
+def get_archive_files(archive: zipfile.ZipFile | rarfile.RarFile) -> list[ArchiveFile]:
+    """Return the image entries of an archive in page order.
+
+    Metadata entries such as ComicInfo.xml are not pages. Counting them would make
+    page_count disagree with the page list the reader uses, so a book could never
+    be marked as finished.
+    """
+    result = []
+    for name in sorted(archive.namelist()):
+        if name.endswith('/'):
+            continue
+        mime_type = mimetypes.guess_type(name)[0]
+        if not mime_type or name.lower().endswith('.xml'):
+            continue
+        result.append(ArchiveFile(name, mime_type))
+    return result