Metadata description shoudn't be hard-coded

The website seems to use the same, hardcoded value for the 'description' elements in metadata (eg for the Open Graph protocol, for Twitter cards, etc). See below for a HTML snippet. Ideally, the metadata reflects the content of the page. For example, for a blog post, that 'description' _should_ be the (custom) summary of the blog post (see also https://github.com/xsf/xmpp.org/issues/1581 ). This would greatly improve the rendering of links. Take, for example, this screenshot from Slack. It uses the generic description, instead of the summary of the blog post. That doesn't look great. <img width="1207" height="424" alt="Image" src="https://github.com/user-attachments/assets/94d57669-f16d-4fb4-8b82-a3633bc3b839" /> Ideally, that screenshot should have included this text (which is the custom summary of the article): > Healthcare messaging must be secure, interoperable, and compliant, yet too often relies on closed consumer platforms. In the Netherlands, the forthcoming NTA 7532 specification aims to provide a national framework for secure, auditable communication between healthcare professionals. This open letter explains how the XMPP standard offers a proven foundation for NTA 7532, supporting vendor-independent and interoperable messaging. By engaging with initiatives like NTA 7532, the XSF promotes open, privacy-respecting communication technologies and invites collaboration with Dutch healthcare stakeholders and the global XMPP community. Even the non-custom summary would probably be an improvement over this hard-coded text. ```html <meta name="description" content="XMPP is the Extensible Messaging and Presence Protocol, a set of open technologies for instant messaging, presence, multi-party chat, voice and video calls, collaboration, lightweight middleware, content syndication, and generalized routing of XML data."> <meta property="og:url" content="https://xmpp.org/"> <meta property="og:type" content="website"> <meta property="og:title" content="XMPP - The universal messaging standard"> <meta property="og:description" content="XMPP is the Extensible Messaging and Presence Protocol, a set of open technologies for instant messaging, presence, multi-party chat, voice and video calls, collaboration, lightweight middleware, content syndication, and generalized routing of XML data."> <meta property="og:image" content="/images/logos/xmpp-logo-text-1200px-wide.png"> <meta property="og:image:alt" content="XMPP (Extensible Messaging and Presence Protocol) Logo" /> <meta property="og:image:width" content="1200" /> <meta property="og:image:height" content="630" /> <meta name="twitter:card" content="summary_large_image"> <meta property="twitter:domain" content="xmpp.org"> <meta property="twitter:url" content="https://xmpp.org/"> <meta name="twitter:title" content="XMPP - The universal messaging standard"> <meta name="twitter:description" content="XMPP is the Extensible Messaging and Presence Protocol, a set of open technologies for instant messaging, presence, multi-party chat, voice and video calls, collaboration, lightweight middleware, content syndication, and generalized routing of XML data."> <meta name="twitter:image" content="/images/logos/xmpp-logo-text-1200px-wide.png"> ```