feat: intégration plugin Kirby SEO

- Ajout de tobimori/kirby-seo via Composer
- snippet('seo/head') dans header.php (remplace les meta manuels)
- snippet('seo/schemas') dans footer.php pour JSON-LD
- Onglet SEO ajouté dans site.yml et tous les blueprints de pages
- Configuration SEO dans config.php (sitemap, robots, canonicalBase TODO)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

site/plugins/kirby-seo/classes/Buttons/RobotsViewButton.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace tobimori\Seo\Buttons;
+
+use Kirby\Cms\Page;
+use Kirby\Panel\Ui\Buttons\ViewButton;
+use Kirby\Toolkit\I18n;
+use Kirby\Toolkit\Str;
+
+class RobotsViewButton extends ViewButton
+{
+	public function __construct(Page $model)
+	{
+		$robots = $model->robots();
+
+		$theme = 'positive-icon';
+		$icon = 'robots';
+		$text = I18n::translate('seo.fields.robots.indicator.index');
+
+		if (Str::contains($robots, 'no') && !Str::contains($robots, 'noindex')) {
+			$theme = 'notice-icon';
+			$icon = 'robots-off';
+			$text = I18n::translate('seo.fields.robots.indicator.any');
+		}
+
+		if (Str::contains($robots, 'noindex')) {
+			$theme = 'negative-icon';
+			$icon = 'robots-off';
+			$text = I18n::translate('seo.fields.robots.indicator.noindex');
+		}
+
+		parent::__construct(
+			model: $model,
+			icon: $icon,
+			text: $text,
+			theme: $theme,
+			link: $model->panel()->url() . '?tab=seo',
+			responsive: true
+		);
+	}
+}