CLAUDE.md: document datacenter pages and IndexNow

Assisted-by: Claude:opus-5

CLAUDE.md

@@ -134,6 +134,8 @@ A second public site served from the **same process** on `BINGO_HOST` (`datacent
 - Ordering: `position` is dense 1..N (`Bingo.place!` inserts and shifts, `renumber!` after deletes). The card shows positions 1–25; anything beyond is reserve. Slug is fixed at creation (it names photo objects).
 - Photos: stored in the existing bucket under `bingo/<slug>-<hex>.<ext>` (no storage-repo change), proxied by `BingoWeb` at `/p/:file` with immutable caching (new upload = new key; old objects are kept). Type sniffed from magic bytes (JPEG/PNG/WebP), 8 MB cap, metadata stripped (GPS!). URL import is https-only, admin-only. On store, ImageMagick (`convert`, installed in the Dockerfile) derives `-480.webp` (card cells), `-1200.webp` (dialog, JSON-LD) and `-og.jpg` (1200×630 centre crop, og:image); `photo_variants`/`photo_og` record success (rows without `photo_og` use the 1200 WebP as og:image) and the page falls back to the original without them. "Rebuild resized photos" in admin re-derives from stored originals.
 - SEO: `BingoWeb` has `static` off (public/ is asxp.io's), its own `/robots.txt`, `/sitemap.xml` (hreflang alternates, `lastmod` = max `updated_at`), and favicon/apple-touch-icon routes serving `assets/bingo/`. The h1 carries a per-locale `tagline`; `/en/` 301s to `/en`. Per-locale `seo_title`/`seo_desc` with the live score, OG/Twitter tags (og:image = latest hit's photo, alt = its name and city), JSON-LD WebSite + ItemList of Places (`info_url` as `subjectOf`, incidents as `event`). HSTS via Rack::Protection. Canonical/hreflang always use `BINGO_HOST`, so `BINGO_ALT_HOST` doesn't compete.
+- Datacenter pages: `/:locale/dc/:slug` (`views/bingo/dc.erb`) for every row, reserve included. Title/description/facts are generated (`dc_facts`, `dc_title*` strings); optional `about_*` prose (admin form, no fallback across locales). Card cells are `<a>` to these pages, and JS opens the dialog on a plain click. Dialog and page share `_dc_meta`/`_dc_incidents`. The layout takes `@title @desc @path_for @x_default @og @ld @noindex` from the route. The sitemap lists the card and all datacenter pages × locales.
+- IndexNow (`Bingo::IndexNow`): admin incident/DC/sort actions ping api.indexnow.org in a thread with the changed URLs; key from the `INDEXNOW` secret → `INDEXNOW_KEY`, served at `/<key>.txt`. Unset = no-op.
 - Photos are third-party (operator sites, Habr, Wikimedia Commons CC BY-SA) — keep `photo_credit` filled; renders/illustrations are marked as such.
 - No street addresses or coordinates on the page — city level only.
 
@@ -189,6 +191,7 @@ All colors in `public/style.css` are CSS custom properties on `:root` (design to
 | `ASXPIO_S3_ACCESS_KEY`   | MinIO service account key, scoped to `asxpio-invoices`                   | Same dual-repo update. Push storage first.                                                       |
 | `ASXPIO_S3_SECRET_KEY`   | Matching MinIO secret                                                    | Same.                                                                                            |
 | `CRYPTO_ADDRESSES`       | **Seed only.** Imported into `payout_addresses` on the first boot with an empty table; afterwards edited in `/admin/invoices/payout-addresses`. | Delete the secret (and its line in deploy.yaml) once the admin page shows the imported addresses. |
+| `INDEXNOW`               | IndexNow key for the bingo (→ `INDEXNOW_KEY`, served at `/<key>.txt`) | New random key (8–128 chars `A-Za-z0-9-`) → update secret → push. The old key file stops being served. |
 | `LTC_ADDRESS`            | Legacy, seed only (fills LTC on that first import).                      | Delete together with `CRYPTO_ADDRESSES`.                                                         |
 | `DEPLOY_IP/USER/SSH_KEY` | SSH to prod from CI                                                      | Standard SSH key rotation.                                                                       |
 | `FORGEJO_REGISTRY/USER`, `FJ_TOKEN` | Kaniko registry auth. Token needs `write:package` + `read:repository`; named `FJ_` because Forgejo forbids new secrets prefixed `FORGEJO_` | Forgejo token rotation.                                                                          |