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

docs/screenshots/README.md

@@ -0,0 +1,68 @@
+# README screenshots
+
+The screenshots in the main README show a neutral demo library (30 games, persona "Dev"), never real user data.
+They come from the local stack with the WireMock mocks of `ToBePlayed-Core/local/wiremock`.
+
+## Start
+
+1. Start the stack as in the main README, section "Local development without keys".
+2. Open the app in a desktop browser, log in with `dev@localhost` / `password123`, pass the welcome page.
+3. Settings: dark mode on, language English, public profile on.
+4. Dashboard: "Sync now". Wait about one minute: the achievements load one Steam call per second.
+5. Set three things by hand (the sync cannot):
+   - No Man's Sky: status Dropped.
+   - Slay the Spire: "Set to 100%".
+   - Celeste: rating 4 stars, note "Chapter 7 next."
+6. Reload the dashboard and close the "games imported" banner.
+
+## Capture
+
+Set the viewport (browser DevTools device toolbar, or Playwright) to the size in the table. Take a viewport PNG, no
+scaling, not full page.
+
+| File | Viewport | Page and state |
+|---|---|---|
+| `library-desktop-dark.png` | 1280x1022 | `/library`, filter All, sort "Most played", 20 per page |
+| `detail-desktop-dark.png` | 1280x1414 | `/library/504230` (Celeste) |
+| `dashboard-desktop-dark.png` | 1280x1100 | `/dashboard`, banner closed, mouse away from the cards |
+| `library-mobile-dark.png` | 390x1036 | `/library`, same state as desktop |
+| `profile-desktop-dark.png` | 1280x1288 | log out, then `/u/Dev` |
+
+## From the Claude box
+
+The box is itself a container, so the stack differs from the main README. Traps first: the WireMock `-v` path is
+resolved on the Docker host (the mock then loads 0 mappings), and the box reaches sibling containers only through
+the shared network, not through `localhost`.
+
+```
+docker run -d --name tbp_auth_db_local -e POSTGRES_DB=tbp_auth -e POSTGRES_USER=tbp_user -e POSTGRES_PASSWORD=local_secret_password postgres:17-alpine
+docker run -d --name tbp_core_db_local -e POSTGRES_DB=tbp_core -e POSTGRES_USER=tbp_user -e POSTGRES_PASSWORD=local_secret_password postgres:17-alpine
+docker run -d --name tbp_core_mocks_local wiremock/wiremock:3.9.1
+for c in tbp_auth_db_local tbp_core_db_local tbp_core_mocks_local; do docker network connect ai_default $c; done
+docker cp /workspace/private/tbp/ToBePlayed-Core/local/wiremock/. tbp_core_mocks_local:/home/wiremock/
+curl -X POST tbp_core_mocks_local:8080/__admin/mappings/reset
+```
+
+Repeat the `docker cp` and the reset after every mock change. Run the built jars (`target/`) and Vite:
+
+- Auth: `java -jar target/auth-service-0.0.1-SNAPSHOT.jar --spring.profiles.active=local --spring.docker.compose.enabled=false`
+  plus `--spring.datasource.url=jdbc:postgresql://tbp_auth_db_local:5432/tbp_auth`, `--spring.datasource.username=tbp_user`
+  and `--spring.datasource.password=local_secret_password`.
+- Core: the same with `tbp_core_db_local` and `tbp_core`, plus `--app.steam.base-url=$M/steam`,
+  `--app.igdb.base-url=$M/igdb`, `--app.igdb.token-base-url=$M/twitch`, `--app.psn.auth-base-url=$M/psn/auth`,
+  `--app.psn.api-base-url=$M/psn` and `--app.speedrun.base-url=$M/speedrun`. `M` is `http://<mock container IP>:8080`
+  (`docker inspect tbp_core_mocks_local`): Java rejects the underscore in the container name.
+- Frontend: `VITE_API_URL=http://localhost:8080 VITE_CORE_API_URL=http://localhost:8090 npx vite --port 5173`.
+
+When done, stop the three processes and `docker rm -f` the three containers.
+
+## Rules
+
+- Only the demo persona may appear: name "Dev", Steam ID `76561198000000001`, the default avatar.
+- Keep the file names. Keep each file below about 500 KB.
+- Look at every image before you commit it.
+
+## Data
+
+The 30 games, their achievements and the profile are in `ToBePlayed-Core/local/wiremock`.
+`LocalMocksParseTest` checks that the files fit the Core types and that every achievement stub belongs to an owned game.