feat(solutions): build 5-page Solutions section

Implements the 5 Solutions pages (1 hub + 4 tier detail) with full EN copy
from PDF Strategie & Contenu D.2-D.6.

Architecture
- inc/solutions-data.php: single PHP array keyed by slug, holds the 4 tiers
  (my-proserve, proserve-flex, proserve-academy, customization). Each tier
  declares its hero, sections, and optional upsell. Section schema supports
  4 types: prose / cards / list / cta.
- template-parts/solution-detail.php: reusable partial that iterates the
  sections of a tier and renders each per its type. Alternates light/dark
  backgrounds for visual rhythm.
- templates/page-solution-detail.php: WP custom Page Template
  ("Template Name: Solution Detail"). Looks up the current page slug,
  pulls the matching tier from solutions-data.php, and hands off to the
  partial. Falls back gracefully if the slug is unknown.
- templates/page-solutions-overview.php: WP custom Page Template
  ("Template Name: Solutions Overview") for /solutions/. Renders the
  3-tier comparison table + PROSERVE+ teaser.

Pages were seeded into the DB by a one-shot mu-plugin
(wp-content/mu-plugins/asterion-seed-solutions.php in LocalWP) that
created the parent /solutions/ page and 4 children with the right
post_parent + _wp_page_template, then self-deleted.

Verified all 5 URLs return HTTP 200:
  /solutions/                  62 KB
  /solutions/my-proserve/      65 KB
  /solutions/proserve-flex/    65 KB
  /solutions/proserve-academy/ 63 KB
  /solutions/customization/    62 KB

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

wp-content/themes/asterion-bricks/templates/page-solution-detail.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * Template Name: Solution Detail
+ *
+ * Custom page template assigned to /solutions/my-proserve/, /solutions/proserve-flex/,
+ * /solutions/proserve-academy/ and /solutions/customization/.
+ *
+ * Looks up the page slug in inc/solutions-data.php, hands the matched array off
+ * to template-parts/solution-detail.php, and renders the result wrapped in the
+ * standard header + footer.
+ *
+ * @package AsterionBricks
+ */
+defined('ABSPATH') || exit;
+
+$slug = get_post_field('post_name', get_queried_object_id());
+$data = include AV_THEME_DIR . '/inc/solutions-data.php';
+
+if (! isset($data[$slug])) {
+    // Fallback : fall back to the basic page rendering if the slug isn't mapped.
+    get_header();
+    echo '<section class="av-section"><div class="av-container">';
+    echo '<h1>' . esc_html(get_the_title()) . '</h1>';
+    echo '<p>' . esc_html__('Solution data not found for slug:', 'asterion-bricks') . ' ' . esc_html($slug) . '</p>';
+    echo '</div></section>';
+    get_footer();
+    return;
+}
+
+get_header();
+set_query_var('av_solution', $data[$slug]);
+get_template_part('template-parts/solution-detail');
+get_footer();