bingo: SEO pass and resized photos

The bingo host fell through to asxp.io's public/, so crawlers got
asxp.io's robots.txt pointing at asxp.io's sitemap (and the keys and
invoice JS were served too). Turn static files off for BingoWeb and give
it its own robots.txt and a sitemap with hreflang alternates.

The card loaded 15.6 MB of full-size photos as cell backgrounds. Derive
480/1200 px WebP variants with ImageMagick on store (memory/area limits,
input coder pinned to the sniffed type), render cells as <img> with lazy
loading past the first two rows, and add an admin action that rebuilds
variants from the stored originals.

Head gets per-locale titles and descriptions carrying the live score,
og:image from the latest hit, Twitter card, og:locale alternates,
JSON-LD WebSite + ItemList, and Vary: Accept-Language on the redirect.

Assisted-by: Claude:opus-5

Dockerfile

@@ -3,6 +3,7 @@ FROM ruby:3.4-slim-bookworm
 RUN apt-get update && apt-get install -y --no-install-recommends \
     build-essential \
     libpq-dev \
+    imagemagick \
  && rm -rf /var/lib/apt/lists/*
 
 RUN groupadd -g 11000 asxpio \