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.

compose.yaml

@@ -70,7 +70,7 @@ services:
       WP_REDIS_PORT: ${WP_REDIS_PORT:-6379}
       WP_REDIS_PASSWORD: ${WP_REDIS_PASSWORD:-}
       WP_REDIS_DATABASE: ${WP_REDIS_DATABASE:-}
-      WP_EXTRA_PLUGINS: ${WP_EXTRA_PLUGINS:-post-views-counter seo-by-rank-math google-site-kit}
+      WP_EXTRA_PLUGINS: ${WP_EXTRA_PLUGINS:-post-views-counter seo-by-rank-math google-site-kit fluentform fluent-crm fluent-smtp}
       WP_LOCALE: ${WP_LOCALE:-pt_BR}
       WP_SKIP_UPDATES: ${WP_SKIP_UPDATES:-}
       WP_THEME: ${WP_THEME:-gustavoo-portfolio}