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/Ai/Drivers/OpenAi.php

@@ -0,0 +1,118 @@
+<?php
+
+namespace tobimori\Seo\Ai\Drivers;
+
+use Generator;
+use tobimori\Seo\Ai\Chunk;
+use tobimori\Seo\Ai\Content;
+use tobimori\Seo\Ai\Driver;
+use tobimori\Seo\Ai\SseStream;
+
+class OpenAi extends Driver
+{
+	protected const string DEFAULT_ENDPOINT = 'https://api.openai.com/v1/responses';
+	protected const string DEFAULT_MODEL = 'gpt-5-mini-2025-08-07';
+
+	/**
+	 * @inheritDoc
+	 */
+	public function stream(
+		array $content,
+		string|null $model = null,
+	): Generator {
+		$apiKey = $this->config('apiKey', required: true);
+		$headers = [
+			'Content-Type: application/json',
+			'Accept: text/event-stream',
+			"Authorization: Bearer {$apiKey}",
+		];
+		if ($organization = $this->config('organization')) {
+			$headers[] = "OpenAI-Organization: {$organization}";
+		}
+
+		$payload = [
+			'model' => $model ?? $this->config('model', static::DEFAULT_MODEL),
+			'input' => $this->buildInput($content),
+			// instructions does not work for e.g. openrouter so let's just put everything in user prompt
+			'stream' => true,
+		];
+
+		$stream = new SseStream($this->config('endpoint', static::DEFAULT_ENDPOINT), $headers, $payload, (int)$this->config('timeout', 120));
+		yield from $stream->stream(function (array $event): Generator {
+			$type = $event['type'] ?? null;
+
+			if ($type === 'response.created') {
+				yield Chunk::streamStart($event);
+				return;
+			}
+
+			if ($type === 'response.in_progress') {
+				yield Chunk::textStart($event);
+				return;
+			}
+
+			if ($type === 'response.output_text.delta') {
+				$delta = $event['delta'] ?? '';
+				if ($delta !== '') {
+					yield Chunk::textDelta($delta, $event);
+				}
+				return;
+			}
+
+			if ($type === 'response.output_text.done') {
+				yield Chunk::textComplete($event);
+				return;
+			}
+
+			if ($type === 'response.completed') {
+				yield Chunk::streamEnd($event);
+				return;
+			}
+
+			if ($type === 'response.output_item.added' && ($event['item']['type'] ?? null) === 'reasoning') {
+				yield Chunk::thinkingStart($event);
+				return;
+			}
+
+			if ($type === 'response.error') {
+				$message = $event['error']['message'] ?? 'Unknown OpenAI streaming error.';
+				yield Chunk::error($message, $event);
+			}
+		});
+	}
+
+	/**
+	 * Translates an array of Content messages into the OpenAI Responses API input format.
+	 *
+	 * @param array<Content> $content
+	 */
+	private function buildInput(array $content): array
+	{
+		$input = [];
+
+		foreach ($content as $message) {
+			$blocks = [];
+
+			foreach ($message->blocks() as $block) {
+				if ($block['type'] === 'image') {
+					$blocks[] = [
+						'type' => 'input_image',
+						'image_url' => "data:{$block['mediaType']};base64,{$block['data']}",
+					];
+				} elseif ($block['type'] === 'text') {
+					$blocks[] = [
+						'type' => 'input_text',
+						'text' => $block['text'],
+					];
+				}
+			}
+
+			$input[] = [
+				'role' => $message->role(),
+				'content' => $blocks,
+			];
+		}
+
+		return $input;
+	}
+}