wp-init: provision fluent plugins via WP_EXTRA_PLUGINS

gustavoo-portfolio-core refuses to activate without fluentform, fluent-crm
and fluent-smtp, but those were gitignored and not installed by the setup:
any fresh clone ended with the core plugin inactive and the seeder skipped.
They are now part of the default WP_EXTRA_PLUGINS (verified slugs on
WordPress.org), with .env.example, compose default, README and .gitignore
updated to match.

README.md

@@ -116,7 +116,7 @@ O serviço `wpcli` roda o `docker/wp-init.sh` e detecta o estado do banco:
 **Primeira execução (banco vazio) — instalação**
 1. `wp core install` com URL/título/admin definidos no `.env`
 2. Pacote de idioma `pt_BR`
-3. Instala do WordPress.org os plugins de `WP_EXTRA_PLUGINS` (Post Views Counter, Rank Math SEO, Site Kit) — só se faltarem
+3. Instala do WordPress.org os plugins de `WP_EXTRA_PLUGINS` (Post Views Counter, Rank Math SEO, Site Kit, Fluent Forms, FluentCRM, FluentSMTP) — só se faltarem
 4. Ativa **todos** os plugins de `wp-content/plugins/` e remove os que o WordPress traz (`akismet`, `hello`)
 5. Redis: constantes no `wp-config.php`, plugin, drop-in `object-cache.php` e verificação de conexão
 6. Configura o Post Views Counter: conta **posts e páginas**, posição **Manual only**