Please add mw.wikibase.getEntityObject by site link (title) Lua function just like https://www.wikidata.org/wiki/Special:ItemByTitle or wbgetentities API module with titles parameter. It would be nice with and without language code or site code.
On **cswiki** articles translated from other language wikis are marked by Translated template (with source wiki, article and revision parameters filled in). The template could detect (using Module:Wikidata), whether the article is connected with that source article and categorize it if not. But if that source article is connected with other article in home wiki, it is false positive there (could be categorized too, but in a different maintenance category). I can not single out these false positives, because I can find out (using Lua function in Module:Wikidata), if there is an article in home wiki for any Q-ID given. But I can not find out that Q-ID for any wiki:page pair given.
On **enwiki** in Module:Wikidata talk page is another request from @czar: [[https://en.wikipedia.org/wiki/Wikipedia_talk:Wikidata#QID_lookup_from_enwp_article_title|QID lookup from enwp article title]].