fix(chatt): the OG card showed the atlas, and the brainstorm post had no way forward

docs/social/ride-the-open-source-city-facebook.md

@@ -0,0 +1,36 @@
+# Facebook post — "Ride an open-source city"
+
+Companion social copy for the blog post `public/blog/ride-the-open-source-city.md`.
+Not published by the site (lives outside `public/blog/` so the blog generator never ingests it).
+Paste the plain text below into Facebook.
+
+**Which link previews:** Facebook renders the Open Graph (OG) card for the **first** URL in the
+post. Keep the blog-post URL first so the "Ride an open-source city" card shows; the Play link is
+second as a direct call to action.
+
+---
+
+## Primary post
+
+🚲 You can now ride a bike through Chattanooga — in a browser tab.
+
+I turned the 3D city twin I've been building into something you can actually move through. Roughly 8,000 buildings at real rooftop heights, first person, hop on a bicycle (press B), no install. Fair warning: it's an early beta and genuinely rough — right now you might even spawn under the city and fall through the sky. Catching stuff like that is the whole point, so come break it and tell me the one thing that felt wrong.
+
+The whole thing runs on an open-source Three.js game engine (MIT licensed) — clone it, fork it, keep it. And you don't need money to get involved: playtest it, fork it, file a bug. Learning is free, contribution is the currency, and I build this stuff live on Twitch.
+
+Full story, plus how the free repo ramps up to real help:
+https://scripthammer.com/blog/ride-the-open-source-city
+
+Or just ride it now:
+https://scripthammer.com/chatt/?diorama&walk
+
+#opensource #threejs #gamedev #Chattanooga #webdev #reactjs
+
+---
+
+## Short variant
+
+🚲 Ride an open-source city. I made the 3D Chattanooga twin walkable — first person, hop on a bike, all in a browser tab. Beta, rough, and looking for players. Free and MIT.
+
+Story: https://scripthammer.com/blog/ride-the-open-source-city
+Play: https://scripthammer.com/chatt/?diorama&walk

public/blog/playable-city-chattanooga.md

@@ -24,6 +24,8 @@ twitterCard: summary_large_image
 
 A while back I built a 3D digital twin of Chattanooga. It's about eight thousand buildings at real rooftop heights, floating over the actual street grid and terrain, running in a browser tab. You can [walk the atlas yourself](https://scripthammer.com/chatt/); it's the honest version of the city, drawn from open data with no server behind it.
 
+> 🚲 **Update (August 2026):** the twin isn't read-only anymore. You can now [walk and ride a bike through it](https://scripthammer.com/blog/ride-the-open-source-city) in first person. This post is the brainstorm that came first; that one is where it actually started moving.
+
 Then I made the mistake of leaving it open on a second monitor for a week. And a question started nagging at me that I can't shake:
 
 **What if the map weren't just something you _look at_, but something you _play_?**

src/app/chatt/page.tsx

@@ -11,7 +11,7 @@ export const metadata: Metadata = {
     description:
       '8,000 buildings at real lidar heights over live OpenStreetMap and USGS 3DEP terrain, in your browser. Open source — join in at Chattanooga.Digital.',
     path: '/chatt/',
-    image: '/chatt-atlas-og.jpg',
+    image: '/chatt-diorama-og.jpg',
   }),
   // The helper derives BOTH canonical and og:url from `path` (metadata.tsx:40).
   // og:url should be what people share (/chatt/), but canonical must stay the