R3: split the landing into its own static container

- gateway/Dockerfile gains a `landing` target: caddy:2-alpine + the shared
  Vite build (identical build args keep the ui stage a single cached build);
  the gateway target drops landing.html from the embed.
- The contour caddy routes /app/, /telegram/ and the Connect path to the
  gateway; the catch-all — the landing at / and any stray path — goes to the
  new landing service, so junk traffic is absorbed by static file serving.
- deploy/landing/Caddyfile mirrors the webui caching (immutable assets,
  no-cache shells) and falls back unknown paths to the landing shell.
- The gateway's / now 308-redirects to /app/ (keeps a local no-caddy run
  usable); webui placeholder landing.html removed.
- CI deploy probe checks both / (landing) and /app/ (gateway).

Verified: both images build; the landing container serves landing.html at /
(no-cache) with junk-path fallback; the gateway image redirects / to /app/
and carries no landing content.

.gitea/workflows/ci.yaml

@@ -298,17 +298,21 @@ jobs:
           # pick up the fresh config.
           docker compose --ansi never up -d --force-recreate --no-deps caddy otelcol prometheus tempo grafana
 
-      - name: Probe the gateway through caddy
+      - name: Probe the landing and the gateway through caddy
         run: |
           set -u
+          # Two probes through the contour caddy (R3 split): "/" is the static
+          # landing container, "/app/" is the gateway-served SPA shell.
           for i in $(seq 1 20); do
-            if docker run --rm --network edge alpine:3.20 wget -q -T 5 -O /dev/null http://scrabble/; then
-              echo "healthy: GET http://scrabble/"
+            if docker run --rm --network edge alpine:3.20 wget -q -T 5 -O /dev/null http://scrabble/ &&
+               docker run --rm --network edge alpine:3.20 wget -q -T 5 -O /dev/null http://scrabble/app/; then
+              echo "healthy: GET http://scrabble/ (landing) + /app/ (gateway)"
               exit 0
             fi
             sleep 3
           done
-          echo "probe failed; recent gateway logs:"
+          echo "probe failed; recent landing + gateway logs:"
+          docker logs --tail 50 scrabble-landing || true
           docker logs --tail 50 scrabble-gateway || true
           exit 1
 

deploy/caddy/Caddyfile

@@ -1,7 +1,9 @@
 # Edge reverse proxy for the Scrabble contour. A single Basic-Auth gate covers
 # every operator surface under /_gm (the backend-rendered admin console and the
-# Grafana subpath); everything else (the SPA at / and /telegram/, plus the
-# Connect edge) goes to the gateway. Mirrors ../galaxy-game's /_gm model.
+# Grafana subpath); the game SPA (/app/, /telegram/) and the Connect edge go to
+# the gateway; the catch-all — notably the public landing at / — goes to the
+# static landing container (R3), so stray traffic never reaches the Go edge.
+# Mirrors ../galaxy-game's /_gm model.
 #
 # CADDY_SITE_ADDRESS is ":80" in the test contour (the host caddy terminates TLS
 # and forwards); set it to a domain in prod (Stage 18) so this caddy does its own
@@ -36,8 +38,14 @@
 		}
 	}
 
-	# The SPA (/, /telegram/) and the Connect edge are served by the gateway.
-	handle {
+	# The game SPA and the Connect edge are served by the gateway.
+	@gateway path /app /app/* /telegram /telegram/* /scrabble.edge.v1.Gateway/*
+	handle @gateway {
 		reverse_proxy gateway:8081
 	}
+
+	# Everything else — the public landing at / and any stray path — is static.
+	handle {
+		reverse_proxy landing:80
+	}
 }

deploy/docker-compose.yml

@@ -75,6 +75,7 @@ services:
     build:
       context: ..
       dockerfile: gateway/Dockerfile
+      target: gateway
       args:
         VITE_TELEGRAM_BOT_ID: ${VITE_TELEGRAM_BOT_ID:-}
         VITE_TELEGRAM_LINK: ${VITE_TELEGRAM_LINK:-}
@@ -100,6 +101,28 @@ services:
       # caddy owns the /_gm Basic-Auth and routes /_gm to the backend directly.
     networks: [internal]
 
+  # --- Landing (static) -------------------------------------------------------
+  # The public landing page in its own caddy container (R3): the contour caddy
+  # routes the catch-all (notably /) here, the gateway keeps only /app/,
+  # /telegram/ and the Connect edge. Shares the gateway Dockerfile's UI build
+  # stage — identical build args keep that stage a single cached build.
+  landing:
+    container_name: scrabble-landing
+    image: scrabble-landing:latest
+    build:
+      context: ..
+      dockerfile: gateway/Dockerfile
+      target: landing
+      args:
+        VITE_TELEGRAM_BOT_ID: ${VITE_TELEGRAM_BOT_ID:-}
+        VITE_TELEGRAM_LINK: ${VITE_TELEGRAM_LINK:-}
+        VITE_TELEGRAM_GAME_CHANNEL_NAME_EN: ${VITE_TELEGRAM_GAME_CHANNEL_NAME_EN:-}
+        VITE_TELEGRAM_GAME_CHANNEL_NAME_RU: ${VITE_TELEGRAM_GAME_CHANNEL_NAME_RU:-}
+        VITE_GATEWAY_URL: ${VITE_GATEWAY_URL:-}
+        VITE_APP_VERSION: ${APP_VERSION:-dev}
+    restart: unless-stopped
+    networks: [internal]
+
   # --- Telegram connector (egress via the VPN sidecar) -----------------------
   vpn:
     container_name: scrabble-telegram-vpn
@@ -145,12 +168,13 @@ services:
       OTEL_EXPORTER_OTLP_ENDPOINT: http://otelcol:4317
       OTEL_EXPORTER_OTLP_INSECURE: "true"
 
-  # --- Edge reverse proxy (single /_gm Basic-Auth; SPA + Connect -> gateway) --
+  # --- Edge reverse proxy (single /_gm Basic-Auth; SPA + Connect -> gateway;
+  #     the catch-all incl. the landing -> the static landing container) -------
   caddy:
     container_name: scrabble-caddy
     image: caddy:2-alpine
     restart: unless-stopped
-    depends_on: [gateway, backend, grafana]
+    depends_on: [gateway, backend, grafana, landing]
     environment:
       # Test: ":80" (host caddy terminates TLS). Prod: a domain for own ACME.
       CADDY_SITE_ADDRESS: ${CADDY_SITE_ADDRESS:-:80}

deploy/landing/Caddyfile

@@ -0,0 +1,27 @@
+# Static landing container (R3). Serves the public landing page and the built
+# assets it references at /; the game SPA (/app/, /telegram/) and the Connect
+# edge stay on the gateway. The contour caddy routes the catch-all here, so
+# stray public paths are absorbed by static file serving and never reach the Go
+# edge. This file is baked into the image at build time (gateway/Dockerfile,
+# target `landing`), not bind-mounted.
+{
+	admin off
+}
+
+:80 {
+	root * /srv
+	encode zstd gzip
+
+	# Mirror the gateway webui caching: hash-named build assets are immutable,
+	# every HTML shell is no-cache so a new deploy is picked up immediately.
+	header /assets/* Cache-Control "public, max-age=31536000, immutable"
+	@shell not path /assets/*
+	header @shell Cache-Control "no-cache"
+
+	# An unknown path falls back to the landing shell (the gateway's old "/"
+	# behaviour); "/" itself resolves through the index below.
+	try_files {path} /landing.html
+	file_server {
+		index landing.html
+	}
+}

gateway/Dockerfile

@@ -1,15 +1,18 @@
-# Multi-stage build for the gateway service. A node stage builds the static UI
-# (Vite), the result is embedded into the Go binary (gateway/internal/webui/dist),
-# and the Go stage — mirroring platform/telegram/Dockerfile — yields a static
-# binary shipped on distroless nonroot. So the single binary serves the SPA at /
-# and /telegram/ (docs/ARCHITECTURE.md §13) with no separate static container.
+# Multi-stage build for the gateway service and the landing image. A node stage
+# builds the static UI (Vite) once; the `landing` target serves that build from a
+# static caddy container (the public landing at /, R3), while the final gateway
+# target embeds it — minus landing.html — into the Go binary
+# (gateway/internal/webui/dist), which serves the game SPA at /app/ and
+# /telegram/ (docs/ARCHITECTURE.md §13). The Go stage mirrors
+# platform/telegram/Dockerfile and ships on distroless nonroot.
 #
 # The production UI build vars are image build-args, baked into the bundle.
-# Build from the repository root so go.work, pkg/, gateway/ and ui/ are all in the
-# Docker context:
+# Build from the repository root so go.work, pkg/, gateway/, ui/ and
+# deploy/landing/ are all in the Docker context:
 #   docker build -f gateway/Dockerfile \
 #     --build-arg VITE_GATEWAY_URL=https://example \
 #     -t scrabble-gateway .
+#   docker build -f gateway/Dockerfile --target landing -t scrabble-landing .
 
 # --- UI build ----------------------------------------------------------------
 FROM node:22-alpine AS ui
@@ -38,6 +41,14 @@ RUN pnpm install --frozen-lockfile
 COPY ui ./
 RUN pnpm build
 
+# --- landing -------------------------------------------------------------------
+# The public landing page as its own static container (R3): the same Vite build
+# served by caddy at /, so stray public traffic is absorbed by static file
+# serving and never reaches the Go edge.
+FROM caddy:2-alpine AS landing
+COPY deploy/landing/Caddyfile /etc/caddy/Caddyfile
+COPY --from=ui /ui/dist /srv
+
 # --- Go build ----------------------------------------------------------------
 FROM golang:1.26.3-alpine AS build
 WORKDIR /src
@@ -46,9 +57,11 @@ COPY pkg ./pkg
 COPY gateway ./gateway
 
 # Replace the committed placeholder with the freshly built UI before compiling, so
-# go:embed bakes the real bundle into the binary.
+# go:embed bakes the real bundle into the binary. The landing shell ships in the
+# landing image, not in the gateway (R3).
 RUN rm -rf gateway/internal/webui/dist
 COPY --from=ui /ui/dist gateway/internal/webui/dist
+RUN rm gateway/internal/webui/dist/landing.html
 
 # Reduce the workspace to what the gateway needs: gateway + pkg (loadtest is not in
 # this context; its scrabble/gateway replace targets ./gateway, which is present here).
@@ -56,6 +69,6 @@ RUN go work edit -dropuse=./backend -dropuse=./platform/telegram -dropuse=./load
 RUN CGO_ENABLED=0 GOOS=linux go build -trimpath -o /out/gateway ./gateway/cmd/gateway
 
 # --- runtime -----------------------------------------------------------------
-FROM gcr.io/distroless/static-debian12:nonroot
+FROM gcr.io/distroless/static-debian12:nonroot AS gateway
 COPY --from=build /out/gateway /usr/local/bin/gateway
 ENTRYPOINT ["/usr/local/bin/gateway"]

gateway/internal/connectsrv/server.go

@@ -158,14 +158,16 @@ func (s *Server) HTTPHandler() http.Handler {
 		// does not serve the app shell at the operator path.
 		mux.Handle("/_gm/", http.NotFoundHandler())
 	}
-	// The embedded UI: the game SPA under /app/ (web) and /telegram/ (the Telegram Mini
-	// App), with a separate landing page at the catch-all "/" — the single-origin model
-	// (docs/ARCHITECTURE.md §13). All sit below the h2c wrap so the Connect edge (a more
-	// specific prefix) keeps priority. Each SPA mount falls back to the app shell
-	// (index.html) for the hash router; "/" falls back to the landing (landing.html).
+	// The embedded UI: the game SPA under /app/ (web) and /telegram/ (the Telegram
+	// Mini App) — the single-origin model (docs/ARCHITECTURE.md §13). Both sit below
+	// the h2c wrap so the Connect edge (a more specific prefix) keeps priority, and
+	// each mount falls back to the app shell (index.html) for the hash router. The
+	// public landing moved to its own static container behind the contour caddy
+	// (R3), so the catch-all redirects a stray root hit to the app shell — which
+	// keeps a local no-caddy run usable.
 	mux.Handle("/telegram/", webui.Handler("/telegram/", "index.html"))
 	mux.Handle("/app/", webui.Handler("/app/", "index.html"))
-	mux.Handle("/", webui.Handler("", "landing.html"))
+	mux.Handle("/", http.RedirectHandler("/app/", http.StatusPermanentRedirect))
 	// Every request body on the public listener is capped (the admin proxy POSTs
 	// included); the h2c server carries explicit stream/idle sizing (R3).
 	return h2c.NewHandler(maxBodyHandler(s.maxBodyBytes, mux), &http2.Server{

gateway/internal/connectsrv/server_test.go

@@ -197,6 +197,26 @@ func TestExecuteOversizedPayloadRejected(t *testing.T) {
 	}
 }
 
+// TestRootRedirectsToApp verifies the gateway no longer serves a landing at "/"
+// (it lives in the landing container since R3): a stray root hit is redirected
+// to the app shell.
+func TestRootRedirectsToApp(t *testing.T) {
+	front := httptest.NewServer(connectsrv.NewServer(connectsrv.Deps{}).HTTPHandler())
+	defer front.Close()
+
+	client := &http.Client{CheckRedirect: func(*http.Request, []*http.Request) error {
+		return http.ErrUseLastResponse
+	}}
+	resp, err := client.Get(front.URL + "/")
+	if err != nil {
+		t.Fatalf("get /: %v", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+	if resp.StatusCode != http.StatusPermanentRedirect || resp.Header.Get("Location") != "/app/" {
+		t.Fatalf("GET / = %d -> %q, want 308 -> /app/", resp.StatusCode, resp.Header.Get("Location"))
+	}
+}
+
 func TestExecuteUnknownMessageType(t *testing.T) {
 	client, cleanup := newEdge(t, func(w http.ResponseWriter, r *http.Request) {})
 	defer cleanup()

gateway/internal/webui/dist/landing.html

@@ -1,16 +0,0 @@
-<!doctype html>
-<html lang="en">
-  <head>
-    <meta charset="utf-8" />
-    <meta name="viewport" content="width=device-width, initial-scale=1" />
-    <title>Scrabble</title>
-  </head>
-  <body>
-    <!-- scrabble-landing -->
-    <p>
-      Landing build placeholder. The production gateway image embeds the real Vite
-      build (see gateway/Dockerfile); seeing this page means the binary was built
-      without a UI build.
-    </p>
-  </body>
-</html>

gateway/internal/webui/webui.go

@@ -1,12 +1,13 @@
 // Package webui serves the embedded static UI build over the public edge.
 //
-// The committed dist/ holds only placeholder index.html / landing.html so the gateway
-// module compiles with a plain `go build` (and in CI) without a UI build. The production
-// gateway image replaces dist/ with the real Vite build before compiling (see
-// gateway/Dockerfile), so the binary ships the UI inside it. Because Vite is built with a
-// relative asset base, one build serves under any path: the game SPA is mounted at /app/
-// (web) and /telegram/ (the Telegram Mini App), with a separate landing page at / — the
-// single-origin model in docs/ARCHITECTURE.md §13.
+// The committed dist/ holds only a placeholder index.html so the gateway module
+// compiles with a plain `go build` (and in CI) without a UI build. The production
+// gateway image replaces dist/ with the real Vite build — minus landing.html, which
+// ships in the separate landing container since R3 — before compiling (see
+// gateway/Dockerfile), so the binary ships the UI inside it. Because Vite is built
+// with a relative asset base, one build serves under any path: the game SPA is
+// mounted at /app/ (web) and /telegram/ (the Telegram Mini App) — the single-origin
+// model in docs/ARCHITECTURE.md §13.
 //
 // Caching (Stage 17): Vite emits hash-named files under assets/, so those are immutable and
 // cached hard (a reload/relaunch is a cache hit, not a re-download); the HTML shells carry
@@ -35,10 +36,10 @@ func distFS() fs.FS {
 }
 
 // Handler serves the embedded UI. An existing file is served directly (hash-named assets get
-// an immutable cache); every other path falls back to indexName (the SPA shell or the landing
-// page) so a client-side deep link still loads. When stripPrefix is non-empty it is removed
-// from the request path before lookup, so the same build serves under a sub-path (e.g.
-// "/app/" or "/telegram/").
+// an immutable cache); every other path falls back to indexName (the SPA shell) so a
+// client-side deep link still loads. When stripPrefix is non-empty it is removed from the
+// request path before lookup, so the same build serves under a sub-path (e.g. "/app/" or
+// "/telegram/").
 func Handler(stripPrefix, indexName string) http.Handler {
 	content := distFS()
 	files := http.FileServer(http.FS(content))

gateway/internal/webui/webui_test.go

@@ -22,20 +22,12 @@ func body(t *testing.T, resp *http.Response) string {
 	return string(b)
 }
 
-// TestLandingMountServesLandingAndFallsBack: "/" serves the landing shell (no-cache) and
-// any unknown path falls back to it.
-func TestLandingMountServesLandingAndFallsBack(t *testing.T) {
-	h := Handler("", "landing.html")
-
-	resp := get(t, h, "/")
-	if resp.StatusCode != http.StatusOK || !strings.Contains(body(t, resp), "scrabble-landing") {
-		t.Fatalf("GET / did not serve the landing shell (status %d)", resp.StatusCode)
-	}
-	if cc := get(t, h, "/").Header.Get("Cache-Control"); cc != "no-cache" {
-		t.Errorf("landing Cache-Control = %q, want no-cache", cc)
-	}
-	if resp := get(t, h, "/whatever"); resp.StatusCode != http.StatusOK {
-		t.Fatalf("GET /whatever status = %d, want 200 (fallback)", resp.StatusCode)
+// TestShellNoCache: the served HTML shell carries no-cache so a new deploy's
+// shell (and the asset URLs it references) is fetched fresh.
+func TestShellNoCache(t *testing.T) {
+	h := Handler("/app/", "index.html")
+	if cc := get(t, h, "/app/").Header.Get("Cache-Control"); cc != "no-cache" {
+		t.Errorf("shell Cache-Control = %q, want no-cache", cc)
 	}
 }