{{/* index.html renders the full lectio-web page: top-bar controls (date,
lectionary, version checkboxes, all/gospel toggle, theme select), a
passage-lookup form, and the pre-rendered reading pane (#pane).
The controls form (#controls) carries hx-get="/readings" and fires on
any "change" bubbling up from its fields (htmx auto-includes an
hx-get element's enclosing form fields as the request's query
params -- no hx-include needed). The date +/- buttons are separate
hx-get elements nested in the same form so their own field values are
included too; they override "date" via hx-vals. The theme