fix(analytics): Corregir URLs en analytics usando post_name desde BD

Problema:
- URLs en analytics mostraban dominio incorrecto (HTTP_HOST)
- URLs usaban formato /?p=ID en lugar de permalinks

Solución:
- class-search-engine.php: Agregar propiedad $prefix, incluir p.post_name
  en 5 queries fetch, agregar helpers getSiteUrlFromDb(),
  getPermalinkStructure() y buildPermalink()
- search-endpoint.php: Obtener site_url y permalink_structure desde
  wp_options, construir URLs con post_name
- click-endpoint.php: Fallback de dest usando post_name desde BD

Archivos modificados:
- includes/class-search-engine.php
- api/search-endpoint.php
- api/click-endpoint.php

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

includes/class-shortcode.php

@@ -0,0 +1,125 @@
+<?php
+/**
+ * Shortcode Handler
+ *
+ * @package ROI_APU_Search
+ */
+
+declare(strict_types=1);
+
+// Prevent direct access
+if (!defined('ABSPATH')) {
+    exit;
+}
+
+/**
+ * Handles the [roi_apu_search] shortcode
+ */
+final class ROI_APU_Search_Shortcode
+{
+    /**
+     * Render the shortcode
+     *
+     * @param array|string $atts Shortcode attributes
+     * @return string HTML output
+     */
+    public function render($atts): string
+    {
+        $atts = shortcode_atts([
+            'categories'  => '',       // Comma-separated category IDs or slugs
+            'per_page'    => 10,       // Results per page
+            'placeholder' => 'Buscar analisis de precios unitarios...',
+            'min_chars'   => 3,        // Minimum characters to search
+            'show_info'   => 'true',   // Show search info (total, time)
+        ], $atts, 'roi_apu_search');
+
+        // Generate unique ID for multiple shortcodes on same page
+        $instance_id = 'roi-apu-' . wp_unique_id();
+
+        // Parse categories to validate
+        $categories = $this->sanitize_categories($atts['categories']);
+        $per_page = max(1, min(100, (int) $atts['per_page']));
+        $min_chars = max(1, min(10, (int) $atts['min_chars']));
+        $show_info = filter_var($atts['show_info'], FILTER_VALIDATE_BOOLEAN);
+
+        ob_start();
+        ?>
+        <div id="<?php echo esc_attr($instance_id); ?>"
+             class="roi-apu-search-container"
+             data-categories="<?php echo esc_attr($categories); ?>"
+             data-per-page="<?php echo esc_attr((string) $per_page); ?>"
+             data-min-chars="<?php echo esc_attr((string) $min_chars); ?>"
+             data-show-info="<?php echo esc_attr($show_info ? 'true' : 'false'); ?>">
+
+            <!-- Search Form -->
+            <div class="roi-apu-search-form">
+                <div class="roi-apu-input-wrapper">
+                    <input type="text"
+                           class="roi-apu-search-input"
+                           placeholder="<?php echo esc_attr($atts['placeholder']); ?>"
+                           minlength="<?php echo esc_attr((string) $min_chars); ?>"
+                           maxlength="250"
+                           autocomplete="off">
+                    <button type="button" class="roi-apu-search-btn">
+                        <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" fill="currentColor" viewBox="0 0 16 16">
+                            <path d="M11.742 10.344a6.5 6.5 0 1 0-1.397 1.398h-.001c.03.04.062.078.098.115l3.85 3.85a1 1 0 0 0 1.415-1.414l-3.85-3.85a1.007 1.007 0 0 0-.115-.1zM12 6.5a5.5 5.5 0 1 1-11 0 5.5 5.5 0 0 1 11 0z"/>
+                        </svg>
+                        <span class="roi-apu-btn-text">Buscar</span>
+                    </button>
+                </div>
+                <div class="roi-apu-error" style="display: none;"></div>
+            </div>
+
+            <!-- Loading Indicator -->
+            <div class="roi-apu-loading" style="display: none;">
+                <div class="roi-apu-spinner"></div>
+                <span>Buscando...</span>
+            </div>
+
+            <!-- Search Info -->
+            <div class="roi-apu-info" style="display: none;"></div>
+
+            <!-- Results Container -->
+            <div class="roi-apu-results"></div>
+
+            <!-- Pagination -->
+            <div class="roi-apu-pagination" style="display: none;"></div>
+        </div>
+        <?php
+        return ob_get_clean();
+    }
+
+    /**
+     * Sanitize and validate categories string
+     *
+     * @param string $categories Comma-separated categories
+     * @return string Sanitized categories string
+     */
+    private function sanitize_categories(string $categories): string
+    {
+        if (empty($categories)) {
+            return '';
+        }
+
+        $parts = array_filter(array_map('trim', explode(',', $categories)));
+        $sanitized = [];
+
+        foreach ($parts as $part) {
+            if (is_numeric($part)) {
+                // Validate category exists
+                $term = get_term((int) $part, 'category');
+                if ($term && !is_wp_error($term)) {
+                    $sanitized[] = (int) $part;
+                }
+            } else {
+                // Try by slug
+                $term = get_term_by('slug', sanitize_title($part), 'category');
+                if ($term) {
+                    $sanitized[] = (int) $term->term_id;
+                }
+            }
+        }
+
+        return implode(',', array_unique($sanitized));
+    }
+}