Franchises and timelines: prequel/sequel navigation, franchise index

Movies and series can belong to a timeline (an ordered strand, e.g. "Star Trek — Prime" or "Star Trek — Kelvin"), and timelines can belong to a franchise (e.g. "Star Trek", "Stargate"). Each show/movie page shows a widget < Prequel | Timeline name | Sequel > with the franchise above it; clicking the franchise opens its index. Test: open a Star Trek movie — the widget shows its timeline with prequel/sequel links and "Star Trek" above it; the franchise page lists all timelines and their titles, sortable. Details:

• Creator: "we have franchises, and timelines, and some franchises have multiple timelines ... make them sortable by timeline or release date at shows the release date of the last episode counts. in a show or movie page we show a franchise widget with < Prequel | TimelineName | Sequel > and if the timeline is part of a franchise that franchise is above it and when you click on it you get the franchise index."
• Names: "Franchise" ("Stargate Franchise is clear"; "universe" is taken by Stargate Universe), "Timeline"; navigation /franchises.
• Order within a timeline: in-world order (editable) or release date; for series the release date of the last episode counts.
• Seed: TMDB movie collections (belongs_to_collection) give many timelines for free; franchises and mixed movie+series timelines (Star Trek, Marvel) are edited by hand — needs a small editor for the creator (signed in as az5b2).