feat(icons): load Bootstrap Icons and Font Awesome from the shared platform-tools packs

Register the icons packs in platform_connect, add fit_icon_assets() with local
fallback, and add a sysadmin 'Pacotes de icones' link to platform?tool=icons.

includes/header.php

@@ -33,7 +33,7 @@ $app_name   = defined('APP_NAME') ? APP_NAME : 'FitMe 3070';
     </script>
     <link href="<?= base_url('assets/vendor/bootstrap5/css/bootstrap.min.css') ?>" rel="stylesheet">
     <link href="<?= htmlspecialchars(_asset_versioned('assets/css/bs-brand.css'), ENT_QUOTES) ?>" rel="stylesheet">
-    <link href="<?= base_url('assets/vendor/bootstrap-icons/bootstrap-icons.css') ?>" rel="stylesheet">
+    <?= fit_icon_assets(['bootstrap-icons'], ['assets/vendor/bootstrap-icons/bootstrap-icons.css']) ?>
     <link href="<?= base_url('assets/vendor/summernote/summernote-bs5.min.css') ?>" rel="stylesheet">
     <link href="<?= htmlspecialchars(_asset_versioned('assets/css/backoffice.css'), ENT_QUOTES) ?>" rel="stylesheet">
     <?php include __DIR__ . '/env_ribbon.php';   // moldura de aviso fora de produção ?>
@@ -114,6 +114,10 @@ $app_name   = defined('APP_NAME') ? APP_NAME : 'FitMe 3070';
                   // platform-tools passa a aparecer sozinha, sem precisar de link novo aqui. ?>
             <?= bo_nav_link('platform.php?tool=index', 'bi-cpu', 'Sistema', ['mod' => 'sub',
                 'active' => (($_GET['tool'] ?? 'index') === 'index' && str_contains($_SERVER['REQUEST_URI'] ?? '', 'platform.php'))]) ?>
+            <?php if (function_exists('pt_icon_packs')): // pacotes de ícones só existem no submódulo novo ?>
+            <?= bo_nav_link('platform.php?tool=icons', 'bi-grid-3x3-gap', 'Pacotes de ícones', ['mod' => 'sub',
+                'active' => (($_GET['tool'] ?? '') === 'icons')]) ?>
+            <?php endif; ?>
         <?php bo_nav_group_end(); ?>
         <?php endif; ?>
     </nav>