chore: bump version to 3.2.0-beta.13

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: EstrellaXD

backend/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "auto-bangumi"
-version = "3.2.0-beta.12"
+version = "3.2.0-beta.13"
 description = "AutoBangumi - Automated anime download manager"
 requires-python = ">=3.10"
 dependencies = [