docs(readme): replace screenshots with neutral demo data

Old screenshots showed a real account. Retake them from the local
stack with 30 demo games and persona "Dev". Add a dashboard shot and
docs/screenshots/README.md.
Refs Lobo_Corp/ToBePlayed-Deployment#12

README.md

@@ -5,9 +5,9 @@ you finished. The UI is in German and English, with light and dark mode.
 
 ![Library](docs/screenshots/library-desktop-dark.png)
 
-| Game detail | Public profile | Mobile |
-|---|---|---|
-| ![Game detail](docs/screenshots/detail-desktop-dark.png) | ![Public profile](docs/screenshots/profile-desktop-dark.png) | ![Mobile library](docs/screenshots/library-mobile-dark.png) |
+| Dashboard | Game detail | Public profile | Mobile |
+|---|---|---|---|
+| ![Dashboard](docs/screenshots/dashboard-desktop-dark.png) | ![Game detail](docs/screenshots/detail-desktop-dark.png) | ![Public profile](docs/screenshots/profile-desktop-dark.png) | ![Mobile library](docs/screenshots/library-mobile-dark.png) |
 
 To Be Played is split into three repositories:
 
@@ -365,7 +365,7 @@ other, then start them in this order (Core also starts without Auth and finds it
 3. **Frontend**: in `ToBePlayed-Frontend`, `npm install`, then `npm run dev`, and open `http://localhost:5173`
    (`localhost`, not `127.0.0.1`, so the browser sends the login cookies to every local port). The development
    values must be `VITE_API_URL=http://localhost:8080` and `VITE_CORE_API_URL=http://localhost:8090`.
-4. **Log in** with `dev@localhost` / `password123`. On the dashboard, start a Steam sync: the library fills with 8
+4. **Log in** with `dev@localhost` / `password123`. On the dashboard, start a Steam sync: the library fills with 30
    games, achievements, time to beat, moods, a wishlist and one speedrun game from recorded answers.
 
 The dev user is `PLATFORM_ADMIN`, so user, auditor and admin pages can all be tried ("View as" in the menu