feat(plugins): mangabaka

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/mangabaka/test/fixtures/changes.json

@@ -0,0 +1,4 @@
+{"data":[
+{"type":"upsert","series_id":1,"entry":{"series_id":1,"state":"paused","rating":70,"progress_chapter":13,"progress_volume":2,"start_date":"2024-03-05","finish_date":null,"note":null,"series":{"id":1,"title":"Alpha","type":"manga","state":"active","merged_with":null,"year":2020,"source":{}}}},
+{"type":"delete","series_id":7}
+],"next_cursor":"cur-2"}