Stage 17 round 6 (#13/About): About screen content + app version from git describe

- About screen: prominent localized title (Scrabble / Эрудит (Скрэббл)), a rules link
  (en/ru Wikipedia), and the Random-game / Game-with-friends sections; copy lives in a
  shared aboutContent module (the landing will reuse it). The random-game move limit
  inlines the 24h auto-match clock.
- App version: Vite define __APP_VERSION__ from VITE_APP_VERSION (default 'dev'), wired as
  a Docker build-arg sourced from `git describe --tags --always` in the deploy step — no
  manual version bumps. The fallback keeps a plain/local build working.

.gitea/workflows/ci.yaml

@@ -285,6 +285,9 @@ jobs:
           mkdir -p "$conf"
           cp -r caddy otelcol prometheus tempo grafana "$conf"/
           export SCRABBLE_CONFIG_DIR="$conf"
+          # App version for the About screen: the git tag if present, else the short SHA
+          # (the test checkout is shallow/untagged, so this is the SHA here — fine).
+          export APP_VERSION="$(git -C "$GITHUB_WORKSPACE" describe --tags --always 2>/dev/null || echo dev)"
           docker compose --ansi never build --progress plain
           docker compose --ansi never up -d --remove-orphans
           # The config-only services bind-mount the reseeded config dir. A plain `up -d`