a band chooses whether a rule follows it

The site separates bands with an edge-to-edge line, and it was `index < sections.length - 1` — not a
decision anybody could make. Two bands that belong together, a heading beside its picture and the
carousel that continues it, read as two pages with a rule between them.

Putting both in ONE band does not solve it: a band is one row, so a full-width strip inside a
two-column band overlaps the other column. What was wanted was never one section; it was no line.

A checkbox rather than a field in the draft, because it is a switch — there is nothing to debounce, and
waiting 600ms to watch a line disappear reads as the control not working. Labelled by what it does
rather than as `divider`, which is the column name and says nothing about what you will see.

Still never on the last band: a line above the footer is the footer's own border, twice.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/canvas.ts

@@ -68,6 +68,8 @@ export type CanvasComponent = {
 export type CanvasSection = {
   id: number;
   name: string;
+  /** Whether the page draws a rule beneath this band. */
+  divider?: boolean;
   /** The heading the page draws above the band, or null. Not `name` — see the site's schema. */
   title?: string | null;
   layout: 'one' | 'two';