Share previews

Read the frontend decision record in docs/decisions. Give every public page its own title and a description of at most 160 characters, and add Open Graph and Twitter card tags to each: og:title, og:description, og:url, og:site_name, og:locale and twitter:card set to summary_large_image, with an absolute canonical URL and an absolute image URL with its width, height and alt text. They must be in the HTML the server sends: link crawlers do not run scripts, so a client-rendered application has to prerender these pages or render their head on the server. Make one 1200 by 630 image in the product's look whose text still reads on a small card, and add per-page images only if the pages differ enough to need them. Add a post-deploy check that fetches the main page and its image without a browser, once with the user agent of each of LinkedInBot, facebookexternalhit, Twitterbot and Slackbot, finds the tags and gets a 200 and an image content type, so a bot rule at the edge cannot block them unnoticed. Then show me what a shared link looks like in a preview tool and one chat app.