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.

config/functions.php

@@ -27,6 +27,7 @@ require_once __DIR__ . '/functions_migrations.php';// platform_update.php migrat
 require_once __DIR__ . '/functions_queue.php';          // message_queue + enqueue_*/flush_message
 require_once __DIR__ . '/functions_csrf.php';
 require_once __DIR__ . '/functions_html.php';               // allowlist HTML sanitiser (clean_richtext/clean_map_embed)
+require_once __DIR__ . '/functions_icons.php';         // fit_icon_assets(): pacotes de ícones partilhados + recurso local
 require_once __DIR__ . '/ci_compat.php';                // CI4 view-helper shim (script_tag/link_tag/view/esc/session)
 require_once __DIR__ . '/functions_gyms.php';           // multi-gym: gyms, URL folders, admin gym switcher
 require_once __DIR__ . '/functions_site.php';           // public-site data (site_info/offer/team/modalidades/horario)