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.

site/includes/include.php

@@ -58,8 +58,8 @@ $canonical = $GLOBALS['_canonical_override'] ?? match ($page) {
 <!-- Vendor: Bootstrap 5.3.3 -->
 <?= link_tag('assets/vendor/bootstrap5/css/bootstrap.min.css') ?>
 
-<!-- Vendor: Font Awesome 5 -->
-<?= link_tag('site/assets/fonts/fontawesome/css/all.css') ?>
+<!-- Icons: Font Awesome 6 from the shared platform-tools pack (local FA 5.13.1 as fallback) -->
+<?= fit_icon_assets(['fontawesome'], ['site/assets/fonts/fontawesome/css/all.css']) ?>
 
 
 <!-- App styles (Bootstrap overrides) -->