feat: OG image scraper - auto-fetch recipe images from Pinterest/URLs

- New backend service: og-scraper.service.ts (extracts og:image, og:title, og:description)
- Pinterest support via Twitterbot UA (gets original resolution from i.pinimg.com)
- Works with Chefkoch, Allrecipes, blogs, any site with og:image meta tags
- GET /api/og-preview?url= for preview
- POST /api/recipes/:id/fetch-image to download + process with sharp
- Frontend: 'Bild holen' button appears when source URL is filled
- Auto-fills title & description from OG data if empty
- Images processed to WebP, max 1200px wide

backend/src/routes/og-scrape.ts

@@ -0,0 +1,76 @@
+import { FastifyInstance } from 'fastify';
+import { scrapeOgData } from '../services/og-scraper.service.js';
+import { getDb } from '../db/connection.js';
+import sharp from 'sharp';
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const DATA_DIR = path.resolve(__dirname, '../../data');
+
+export async function ogScrapeRoutes(app: FastifyInstance) {
+  // Preview: Just fetch OG data without downloading
+  app.get('/api/og-preview', async (request, reply) => {
+    const { url } = request.query as { url?: string };
+    if (!url) return reply.status(400).send({ error: 'url parameter required' });
+
+    try {
+      const data = await scrapeOgData(url);
+      return data;
+    } catch (err: any) {
+      return reply.status(502).send({ error: `Failed to scrape: ${err.message}` });
+    }
+  });
+
+  // Download OG image and attach to recipe
+  app.post('/api/recipes/:id/fetch-image', async (request, reply) => {
+    const { id } = request.params as { id: string };
+    const { url } = request.body as { url: string };
+
+    if (!url) return reply.status(400).send({ error: 'url required' });
+
+    const db = getDb();
+    const recipe = db.prepare('SELECT id FROM recipes WHERE id = ?').get(id) as any;
+    if (!recipe) return reply.status(404).send({ error: 'Recipe not found' });
+
+    try {
+      // Scrape OG data
+      const ogData = await scrapeOgData(url);
+      if (!ogData.image) return reply.status(404).send({ error: 'No image found at URL' });
+
+      // Download image
+      const imgRes = await fetch(ogData.image, {
+        headers: { 'User-Agent': 'Mozilla/5.0' },
+        signal: AbortSignal.timeout(15000),
+      });
+      if (!imgRes.ok) throw new Error(`Image download failed: ${imgRes.status}`);
+
+      const buffer = Buffer.from(await imgRes.arrayBuffer());
+
+      // Process with sharp → WebP, max 1200px wide
+      const imgDir = path.join(DATA_DIR, 'images', 'recipes', id);
+      fs.mkdirSync(imgDir, { recursive: true });
+      const imgPath = path.join(imgDir, 'hero.webp');
+
+      await sharp(buffer)
+        .resize(1200, null, { withoutEnlargement: true })
+        .webp({ quality: 85 })
+        .toFile(imgPath);
+
+      // Update recipe
+      const imageUrl = `/images/recipes/${id}/hero.webp`;
+      db.prepare('UPDATE recipes SET image_url = ?, source_url = ?, updated_at = datetime(\'now\') WHERE id = ?')
+        .run(imageUrl, url, id);
+
+      return {
+        ok: true,
+        image_url: imageUrl,
+        og_title: ogData.title,
+        og_description: ogData.description,
+      };
+    } catch (err: any) {
+      return reply.status(502).send({ error: `Failed: ${err.message}` });
+    }
+  });
+}