feat(site): per-gym SEO texts, event gym selector, hero/navbar polish

- Generated SEO titles/descriptions per gym; gym seo fields override each on its own
- Keywords, author, og:site_name, favicon and JSON-LD logo follow the gym
- CrossFit page 404s before output for gyms without a box
- Events: «Mostrar em» gym selector; event page uses its gym's brand
- Hero event button text colour from the event colour (--ev-on)
- Navbar bottom line stops at the other-gym head (--switch-w)
- Diagonal hero blur mask; remove the trial link

views/admin/events/_form.php

@@ -21,6 +21,17 @@ $dt = static function ($v): string {
         <input type="color" class="form-control form-control-color" name="cor" value="<?= htmlspecialchars($data['cor'] ?? '#C2D500') ?>">
     </div>
 
+    <div class="col-md-6">
+        <label class="form-label">Mostrar em</label>
+        <select class="form-select" name="gym_id">
+            <option value="">Todos os ginásios</option>
+            <?php foreach (db_gyms_list($pdo) as $g): ?>
+            <option value="<?= (int) $g['id'] ?>"<?= (int) ($data['gym_id'] ?? 0) === (int) $g['id'] ? ' selected' : '' ?>><?= htmlspecialchars($g['name']) ?></option>
+            <?php endforeach; ?>
+        </select>
+        <div class="form-text">Ginásio em cujo topo da página inicial o destaque aparece.</div>
+    </div>
+
     <div class="col-12">
         <label class="form-label">Subtítulo</label>
         <input class="form-control" name="subtitle" maxlength="255" value="<?= htmlspecialchars($data['subtitle'] ?? '') ?>">

views/admin/events/create.php

@@ -24,6 +24,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         'cta_label'       => trim($_POST['cta_label'] ?? ''),
         'cta_url'         => trim($_POST['cta_url'] ?? ''),
         'show_lead_form'  => isset($_POST['show_lead_form']) ? 1 : 0,
+        'gym_id'          => (int) ($_POST['gym_id'] ?? 0) ?: null,
         'hero_image'      => '',
     ];
 

views/admin/events/edit.php

@@ -48,6 +48,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['save_event'])) {
         'cta_label'       => trim($_POST['cta_label'] ?? ''),
         'cta_url'         => trim($_POST['cta_url'] ?? ''),
         'show_lead_form'  => isset($_POST['show_lead_form']) ? 1 : 0,
+        'gym_id'          => (int) ($_POST['gym_id'] ?? 0) ?: null,
         'hero_image'      => $item['hero_image'],
     ];