Introduces a widget system where domains register UI fragments into
named slots (container_nav, container_card, account_page, account_link).
Host apps iterate widgets generically without naming any domain.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
select_colours was only defined via {% set %} in the root header
template, making it undefined in market/browse nav templates. Moving
it to a Jinja global ensures aria-selected styling works everywhere.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Added app_name Jinja global and aria-selected to nav menu links.
Matches by first path segment (e.g. /market/... → "market") or by
app_name for cross-domain cases (e.g. cart app → "cart" menu item).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
market_url('/product/...') was missing the /<page_slug>/<market_slug>/
prefix required by the market app's route structure. New helper
market_product_url() resolves the prefix from request context
(g.post_slug/g.market_slug in market app, g.page_slug + market_place
in cart app).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
