Produce a comprehensive inventory of everything the current MobileFrontend mobile image viewer does, so we can confirm that the feature parity subtasks under T417678 are complete and nothing has been missed.

Context

The MobileFrontend mobile image viewer is believed to be a fairly simple lightbox, but we need to verify this assumption before committing to a parity checklist. The relevant code spans several files: ImageCarousel, ImageGateway, LoadErrorMessage, the overlay factory, and Minerva init code.

Questions to answer

• What features does the viewer expose to users? (image display, metadata, download, navigation between images, etc.)
• What metadata is displayed and where does it come from?
• Is there any conditional logic? (e.g. features that behave differently on certain wikis, for certain file types, or based on user state)
• How does the viewer handle edge cases? (missing metadata, failed loads, unsupported file types, very large/small images)
• What exclusion rules does it respect? (noviewer, file type filtering, etc.)
• Are there any integration points with other extensions or features we should be aware of? Any gadgets that build on top of this component?

Deliverable

A written summary (comment on this task or on T417678) listing all identified features, with enough detail to confirm or update the subtask list under T417678.