feat(gyms): per-gym brand colour; CrossFit pill follows it

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

views/admin/gyms/_form.php

@@ -86,6 +86,12 @@ foreach (array_keys(gym_sections()) as $k) if (gym_section_on($data, $k)) $secti
         </div>
     </div>
 
+    <div class="col-sm-6 col-lg-4">
+        <label class="form-label" for="brand_color">Cor da marca</label>
+        <input type="color" class="form-control form-control-color" id="brand_color" name="brand_color" value="<?= htmlspecialchars(($data['brand_color'] ?? '') !== '' ? $data['brand_color'] : '#C2D500') ?>">
+        <div class="form-text">Botões, destaques e links do site deste ginásio.</div>
+    </div>
+
     <div class="col-12"><hr class="my-1"><strong>Estado</strong></div>
     <div class="col-md-6">
         <div class="form-check form-switch">