408da3f201
New public ingress and the first network edge. Framework + a vertical slice of operations end-to-end; remaining ops reuse the same transcode pattern in Stage 7. Contracts (new module scrabble/pkg): - push.proto (backend->gateway gRPC server-stream) + scrabble.fbs (FlatBuffers edge payloads), committed generated Go; buf/flatc Makefiles (dev-time codegen). Backend: - REST handlers on the /api/v1 groups: internal session endpoints (telegram/guest/email login -> mint, resolve, revoke) and the user slice (profile, submit_play, state, lobby enqueue/poll, chat). - internal/notify in-process Publisher hub + internal/pushgrpc gRPC server (BACKEND_GRPC_ADDR) streaming your_turn/opponent_moved/chat/nudge/match_found; emission in game.commit, social, matchmaker. - migration 00005 accounts.is_guest; guests are durable rows excluded from stats; ProvisionGuest; email-as-login (RequestLoginCode/LoginWithCode). Gateway (new module scrabble/gateway): - Connect Gateway service over h2c (Execute + Subscribe), FlatBuffers<->JSON transcode registry, Telegram initData HMAC validator (seam), session cache, token-bucket rate limiter (3 classes), push fan-out hub, backend REST + push gRPC client, admin Basic-Auth reverse proxy. go.work: use ./pkg, ./gateway + replace scrabble/pkg. CI: gateway/**, pkg/** path filters; unit build/vet/test span all three modules. Docs (PLAN, ARCHITECTURE, FUNCTIONAL+ru, TESTING, READMEs) updated; gateway/pkg unit tests + guest/email-login integration tests.