Well Layout/Heading Style + Cards Layout configs; wire up Accordion block (#1740)

* Add Layout config (stack/wrap) to the Well block

Companion to flex-pages #(well-wrap-layout branch). Lets editors lay
a well's content out as a wrapping row (e.g. a line of Big Numbers)
instead of only ever stacking it, without a page-specific CSS hack.

* Add accordion StructBlock — flex-page renderer has no CMS wiring yet

flex-page-renderer's Accordion component (type 'accordion') expects
{items: [{header, content, id}], config: [...]}. The only block
registered here under a similar name is the legacy 'faq' StreamBlock
(FAQBlock: question/slug/answer/document/content, no config at all),
which was the renderer's block before it was renamed to 'accordion'
on 2026-06-09 (flex-pages 2d29829) — that rename never got a matching
CMS-side change, so there has been no way to author a working
Accordion block through the CMS since.

This adds a new 'accordion' StructBlock alongside the existing (now
stale) 'faq' entry, matching the renderer's current item shape and
full config set (heading_level, allow_multiple, accent_color,
accent_colors, top_border_color — the last two new in this batch).

Left 'faq' in place rather than removing it: existing pages may still
have content authored in that shape, and auditing/migrating it is a
separate decision from adding accordion support.

* Add Heading Style config (normal/display) to the Well block

Companion to flex-pages "Add Well Heading Style config". Lets editors
render a nested Text block's h6 as a large testimonial-style
pull-quote instead of adding page-specific custom CSS for it.

* Add Layout config (grid/masonry) to the Cards Block

Companion to flex-pages "Add Cards Layout config: grid or masonry".
Lets editors pick a Pinterest-style masonry layout for decorative
card walls (e.g. a wall of quotes) instead of a page-specific CSS
override.

Author: mwvolo

pages/custom_blocks.py

@@ -33,6 +33,21 @@
     ('impact', 'Impact'),
 ]
 
+CARDS_LAYOUT_CHOICES = [
+    ('grid', 'Grid'),
+    ('masonry', 'Masonry (Pinterest-style columns, packed by height)'),
+]
+
+WELL_LAYOUT_CHOICES = [
+    ('stack', 'Stack'),
+    ('wrap', 'Wrap (side by side, reflowing to fewer per row on narrow screens)'),
+]
+
+WELL_HEADING_STYLE_CHOICES = [
+    ('normal', 'Normal'),
+    ('display', 'Display Quote'),
+]
+
 
 class LinksGroupBlock(blocks.StructBlock):
     links = blocks.ListBlock(