feat(offline): implicit net-state model, two-tier version gate, unified lobby

Land the offline-model redesign (ANDROID_PLAN.md O1-O7): replace the explicit offline toggle with a single detected net-state machine, unify the lobby, and add a two-tier client-version gate. Contour-safe: both version vars empty => dormant, the wire change is additive, so web/pwa/vk/tg behaviour is unchanged unless the gate is deliberately configured.

O1 net-state reducer (test-first). O2 store + wiring (connection/offline shims; +@capacitor/network). O3 remove the offline toggle + migrate the pref. O4 two-tier gate: hard update_required degrades to an offline Update/Play-offline notice (not terminal); soft GATEWAY_RECOMMENDED_CLIENT_VERSION -> X-Update-Recommended nudge. O5 unified lobby (device-local + greyed-from-cache server games; self-set identity; closes G-step-0). O6 create flows (with-friends online/offline segment + offline dict guard). O7 docs.

Telegram/VK stay online-only (contour review): the offline model is channel-gated via offlineCapable() (native + plain web; false in the mini-apps). offlineMode.active is hard-gated on it, so the whole model (blue chrome, unified/greyed lobby, transport kill switch, device-local vs_ai/hotseat create) stays inert in Telegram/VK regardless of the detected net state (closing a version-lock path that could have flipped them offline); and New Game's with-friends hides the online/offline segment there, leaving the remote invite alone. ARCHITECTURE already declared "Telegram/VK are exempt" - this makes the code match.

Deploy/CI: wire the version gate through the deploy (GATEWAY_MIN_CLIENT_VERSION + GATEWAY_RECOMMENDED_CLIENT_VERSION as plain unprefixed vars via compose + ci.yaml + prod-deploy.yaml + write-prod-env.sh + .env.example) so the gate is live when set (test-contour commit-hash version fails open; empty => dormant). Disable the manual android-build CI workflow for now (rename .disabled). Bump the app bundle budget 127->130 KB for the added always-loaded wiring. Fix the UI Docker stage (gateway/Dockerfile): install --ignore-scripts so the Alpine/musl SPA build no longer tries to native-build sharp (a local android:assets tool, unused in the image); esbuild's binary is an optional dep so Vite still builds.

Tests: gateway go green (two-tier gate over a real HTTP handler); docker build of the landing + gateway targets green locally; compose --no-interpolate confirms the gateway env; two new telegram.spec.ts e2e (offline signal keeps the chrome online + quick-match opponent choice visible => server enqueue; with-friends shows no pass-and-play), RED-verified; svelte-check 0/0, vitest 617, e2e 248 (chromium + webkit), build + bundle-size 127.8/130.

gateway/internal/connectsrv/server.go

@@ -51,10 +51,15 @@ const honeypotHeader = "X-Scrabble-Honeypot"
 // the edge can turn away a build too old to speak the current wire contract, before it decodes
 // the payload. resultUpdateRequired is the stable envelope result_code — with the Subscribe
 // counterpart connect.CodeFailedPrecondition — that any build, however old, recognises as
-// "you must update". Both are part of the frozen wire contract (docs/ARCHITECTURE.md §2).
+// "you must update". updateRecommendedHeader is the additive, non-blocking soft-tier signal: set
+// on a served Execute response when the client is at or above the hard minimum but below the
+// recommended version, it nudges an update without failing the call. Headers are the
+// version-tolerant layer, so an old client simply ignores it. All part of the frozen wire
+// contract (docs/ARCHITECTURE.md §2).
 const (
-	clientVersionHeader  = "X-Client-Version"
-	resultUpdateRequired = "update_required"
+	clientVersionHeader     = "X-Client-Version"
+	resultUpdateRequired    = "update_required"
+	updateRecommendedHeader = "X-Update-Recommended"
 )
 
 // Limiter classes, the `class` attribute of gateway_rate_limited_total and the
@@ -104,6 +109,12 @@ type Server struct {
 	minClient clientver.Version
 	gateOn    bool
 
+	// recClient is the version below which a served client is nudged to update (the soft tier);
+	// recOn is false when the soft tier is dormant (GATEWAY_RECOMMENDED_CLIENT_VERSION empty or
+	// unparseable). It is independent of the hard gate.
+	recClient clientver.Version
+	recOn     bool
+
 	publicPolicy ratelimit.Policy
 	userPolicy   ratelimit.Policy
 	emailPolicy  ratelimit.Policy
@@ -148,6 +159,9 @@ type Deps struct {
 	// older X-Client-Version is turned away with "update required". Empty or unparseable leaves
 	// the gate dormant.
 	MinClientVersion string
+	// RecommendedClientVersion is the version below which a served client is nudged to update (the
+	// non-blocking X-Update-Recommended header). Empty or unparseable leaves the soft tier dormant.
+	RecommendedClientVersion string
 }
 
 // NewServer constructs the edge service.
@@ -192,6 +206,18 @@ func NewServer(d Deps) *Server {
 			log.Warn("ignoring unparseable MinClientVersion; client-version gate disabled", zap.String("value", d.MinClientVersion))
 		}
 	}
+	// Parse the recommended (soft-tier) version once, the same way. Config.validate already rejects an
+	// unparseable value or one below the minimum, so the warn branch only guards a direct (test)
+	// construction; an empty value leaves the soft tier dormant.
+	var recClient clientver.Version
+	recOn := false
+	if d.RecommendedClientVersion != "" {
+		if v, ok := clientver.Parse(d.RecommendedClientVersion); ok {
+			recClient, recOn = v, true
+		} else {
+			log.Warn("ignoring unparseable RecommendedClientVersion; update-recommended tier disabled", zap.String("value", d.RecommendedClientVersion))
+		}
+	}
 	return &Server{
 		registry:     d.Registry,
 		sessions:     d.Sessions,
@@ -210,6 +236,8 @@ func NewServer(d Deps) *Server {
 		maxBodyBytes: maxBody,
 		minClient:    minClient,
 		gateOn:       gateOn,
+		recClient:    recClient,
+		recOn:        recOn,
 		publicPolicy: ratelimit.PerMinute(rl.PublicPerMinute, rl.PublicBurst),
 		userPolicy:   ratelimit.PerMinute(rl.UserPerMinute, rl.UserBurst),
 		emailPolicy:  ratelimit.Per(rl.EmailPer10Min, 10*time.Minute, rl.EmailBurst),
@@ -335,15 +363,44 @@ func (s *Server) clientTooOld(header string) bool {
 	return clientver.Less(v, s.minClient)
 }
 
+// clientUpdateRecommended reports whether the X-Client-Version header names a version in the soft
+// band — at or above the hard minimum but below the recommended version — so a served response can
+// carry the non-blocking X-Update-Recommended nudge. It fails open exactly like clientTooOld: a
+// dormant soft tier, or an absent or unparseable header, returns false. A client below the minimum is
+// turned away by the hard gate and is never nudged, so it is excluded here too (a dormant hard gate
+// leaves minClient at the zero version, which no real version is below, so the band is simply
+// "below recommended").
+func (s *Server) clientUpdateRecommended(header string) bool {
+	if !s.recOn {
+		return false
+	}
+	v, ok := clientver.Parse(header)
+	if !ok {
+		return false
+	}
+	return !clientver.Less(v, s.minClient) && clientver.Less(v, s.recClient)
+}
+
 // Execute runs one unary operation. Domain failures are returned in the envelope
 // (result_code != "ok", HTTP 200); only edge failures (rate limit, missing
 // session, unknown type, internal) become Connect errors.
-func (s *Server) Execute(ctx context.Context, req *connect.Request[edgev1.ExecuteRequest]) (*connect.Response[edgev1.ExecuteResponse], error) {
+func (s *Server) Execute(ctx context.Context, req *connect.Request[edgev1.ExecuteRequest]) (resp *connect.Response[edgev1.ExecuteResponse], err error) {
 	start := time.Now()
 	msgType := req.Msg.GetMessageType()
 	result := "internal"
 	defer func() { s.metrics.recordEdge(ctx, msgType, result, start) }()
 
+	// The soft-tier nudge rides a response header on any served response (the call still succeeds), so a
+	// client at or above the hard minimum but below the recommended version is told an update is
+	// available without being interrupted. A too-old client (turned away below) or a missing/garbled
+	// version yields no nudge.
+	recommend := s.clientUpdateRecommended(req.Header().Get(clientVersionHeader))
+	defer func() {
+		if recommend && resp != nil {
+			resp.Header().Set(updateRecommendedHeader, "1")
+		}
+	}()
+
 	// The version gate rides the outermost stable layer (an HTTP header) and is checked before
 	// the payload is decoded, so a too-old client makes zero successful calls but sees the
 	// recognizable update_required envelope rather than a decode crash (docs/ARCHITECTURE.md §2).