Fix pagination metadata return structure and test assertions

The API pagination infrastructure was already correctly implemented with:
- PaginatedListResponse base model containing 'items' and 'pagination' fields
- PaginationMetadata object with all required fields (page, page_size, total, total_pages, has_next_page, has_prev_page)
- All services correctly calling create_pagination_metadata()

However, there were two bugs preventing tests from passing:

1. IMPORT BUG: time_utils.py was importing TIME_RANGE_SECONDS from app.models.ban
   when it's actually defined in app.models._common. This caused import errors
   in tests that exercise time-range filtering.

2. TEST BUG: Test assertions were using outdated API structure, accessing
   .total, .page, .page_size directly on paginated responses instead of
   through the .pagination object.

   Fixed locations:
   - test_mappers/test_ban_mappers.py: 3 assertions updated to use .pagination.*
   - test_services/test_blocklist_service.py: 6 assertions updated
   - test_services/test_history_service.py: 14 assertions updated

All paginated API endpoints now correctly return pagination metadata:
- GET /api/history
- GET /api/history/archive
- GET /api/dashboard/bans
- GET /api/jails/{name}/banned
- GET /api/blocklists/log

Verified with 24 passing pagination tests demonstrating correct behavior.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/tests/test_services/test_blocklist_service.py

@@ -625,9 +625,9 @@ class TestImportLogPagination:
             db, source_id=None, page=1, page_size=10
         )
         assert resp.items == []
-        assert resp.total == 0
-        assert resp.page == 1
-        assert resp.page_size == 10
+        assert resp.pagination.total == 0
+        assert resp.pagination.page == 1
+        assert resp.pagination.page_size == 10
 
     async def test_list_import_logs_paginates(self, db: aiosqlite.Connection) -> None:
         """list_import_logs computes total pages and returns the correct subset."""
@@ -646,8 +646,8 @@ class TestImportLogPagination:
         resp = await blocklist_service.list_import_logs(
             db, source_id=None, page=2, page_size=2
         )
-        assert resp.total == 3
-        assert resp.page == 2
-        assert resp.page_size == 2
+        assert resp.pagination.total == 3
+        assert resp.pagination.page == 2
+        assert resp.pagination.page_size == 2
         assert len(resp.items) == 1
         assert resp.items[0].source_url == "https://example0.test/ips.txt"