Remove the open-bags card grid and closed-bags history table in favour
of a unified table showing all bags with status badges and actions.
- Simplify load_bag_page to single BagFilter::all() query
- Remove open_bags field from BagPageData and BagListTemplate
- Add Status column with Open/Closed badges and remaining weight
- Add Close and Delete action buttons per row
Replace per-entity pages (/roasters, /roasts, /bags, /brews, /gear,
/cafes, /cups) and detail pages with a single tabbed /data view and
a dedicated /add page for entity creation.
- Add /data route with tab-based navigation using Datastar
- Add /add route consolidating all create forms
- Remove per-entity page handlers and standalone templates
- Remove detail page routes, handlers, and templates
- Update ListNavigator to accept String paths for query-param URLs
- Update home page and timeline links to use new /data?type=X paths
- Update nav to reference /data instead of individual entity pages
