docs: settle the export docs on the final delivery matrix

ARCHITECTURE: the time zone rides the URL too; 'only degraded platform'
(legacy TG) instead of 'only remaining branch' — the delivery is
per-platform by design now. CLAUDE.md: the renderer joins the build/test
commands and the Dockerfile list.

CLAUDE.md

@@ -128,7 +128,7 @@ platform/telegram/           # Telegram side-service: cmd/validator (HMAC, no VP
 renderer/                    # image-render sidecar (Node + skia-canvas): runs ui/src/lib/gameimage.ts server-side for the finished-game PNG export
 loadtest/                    # module scrabble/loadtest: the load/stress harness
 docs/  .gitea/workflows/  CLAUDE.md  README.md
-backend/Dockerfile gateway/Dockerfile platform/telegram/Dockerfile loadtest/Dockerfile  # multi-stage distroless; gateway/Dockerfile has the `landing` target, platform/telegram/Dockerfile has `validator`+`bot` targets
+backend/Dockerfile gateway/Dockerfile platform/telegram/Dockerfile loadtest/Dockerfile renderer/Dockerfile  # multi-stage distroless (renderer: node:22-slim + skia-canvas + fonts); gateway/Dockerfile has the `landing` target, platform/telegram/Dockerfile has `validator`+`bot` targets
 deploy/                      # docker-compose (+ prod overlay + bot host) + ansible provisioning + caddy + landing + otelcol (OTLP + docker_stats) + prometheus/tempo/grafana + node_exporter + postgres_exporter; prod-deploy.sh
 ```
 
@@ -144,6 +144,7 @@ go run ./backend/cmd/backend    # /healthz, /readyz on :8080
 
 cd ui && pnpm install && pnpm check && pnpm test:unit && pnpm build  # the UI
 pnpm start                      # UI mock mode: lobby -> game, no backend
+cd renderer && pnpm install && pnpm test  # image-render sidecar (bundles ui/src/lib/gameimage.ts, skia smoke)
 
 docker build --build-arg DICT_VERSION=v1.3.0 -f backend/Dockerfile -t scrabble-backend .  # DICT_VERSION required (no default); gateway embeds the SPA
 docker build -f gateway/Dockerfile --target gateway -t scrabble-gateway .

docs/ARCHITECTURE.md

@@ -813,12 +813,12 @@ authenticated caller on a finished game. The PNG is rasterized on demand by the
 **`renderer` sidecar** (internal-only Node + skia-canvas running the same
 `ui/src/lib/gameimage.ts` the web project unit-tests — one renderer, no drift;
 `renderer/README.md`); the backend rebuilds the render payload from the journal +
-`engine.AlphabetTable`, and the client's date locale plus its UI-localized non-play
-labels ride the signed URL so the server render matches the player's presentation.
-Nothing is stored: the artifact is re-derived from the immutable finished journal on
-each GET. The only remaining platform branch is a legacy Telegram client predating
-`downloadFile`, where the GCG falls back to the old clipboard copy and the image option
-is not offered.
+`engine.AlphabetTable`, and the client's date locale, IANA time zone and UI-localized
+non-play labels ride the signed URL so the server render matches the player's
+presentation. Nothing is stored: the artifact is re-derived from the immutable
+finished journal on each GET. The only degraded platform is a legacy Telegram client
+predating `downloadFile`, where the GCG falls back to the old clipboard copy and the
+image option is not offered.
 
 The alphabet-on-the-wire transport does **not** touch this invariant: the live edge
 exchanges alphabet indices, but the persisted journal (and everything derived from it —