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.

.env.example

@@ -46,7 +46,10 @@ WP_THEME=gustavoo-portfolio
 #   post-views-counter  -> contador de views (posts + paginas, posicao manual)
 #   seo-by-rank-math    -> Rank Math SEO (sem configuracao, wizard manual)
 #   google-site-kit     -> Site Kit por Google (sem configuracao, conexao manual)
-WP_EXTRA_PLUGINS=post-views-counter seo-by-rank-math google-site-kit
+#   fluentform, fluent-crm, fluent-smtp -> exigidos pelo gustavoo-portfolio-core
+#     (formularios de contato, feeds do CRM, SMTP); sem eles o plugin
+#     complementar nao ativa e o seeder nao roda.
+WP_EXTRA_PLUGINS=post-views-counter seo-by-rank-math google-site-kit fluentform fluent-crm fluent-smtp
 
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