R4: push enrichment — events carry a state delta, kill the last poll

Enrich the in-app live stream into a delta channel so the UI renders a move from the event without a follow-up game.state, and make the matchmaking poll a stream-down fallback.

- pkg/fbs: trailing fields on opponent_moved (move+game+bag_len), your_turn (move_count), match_found (state), game_over (game), notify (account/invitation/state), MoveResult (rack+bag_len); regenerate Go + TS.
- backend: notify owns the FB encoding (encode.go + payload.go input structs); game/lobby/social map their domain types in. emitMove builds the move delta; game.Service.InitialState feeds match_found/game_started the recipient's initial StateView; friends/invitations notify carry their account/invitation. The move-commit response (submit_play/pass/exchange/resign) returns the actor's refilled rack + bag size.
- gateway: MoveResult transcode carries rack+bag_len.
- ui: pure lib/gamedelta.ts reducer advances the per-game cache keyed on move_count (idempotent + gap-safe); app.svelte seeds the cache on match_found/game_started; Game.svelte applies the delta (commit/pass/exchange/resign drop their load()); NewGame polls only while app.streamAlive is false.
- docs: ARCHITECTURE §10, FUNCTIONAL(+ru), backend/gateway/ui READMEs; PRERELEASE R4 marked done + Refinements.

ui/src/gen/fbs/scrabblefb/game-over-event.ts

@@ -2,6 +2,9 @@
 
 import * as flatbuffers from 'flatbuffers';
 
+import { GameView } from '../scrabblefb/game-view.js';
+
+
 export class GameOverEvent {
   bb: flatbuffers.ByteBuffer|null = null;
   bb_pos = 0;
@@ -41,8 +44,13 @@ scoreLine(optionalEncoding?:any):string|Uint8Array|null {
   return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
 }
 
+game(obj?:GameView):GameView|null {
+  const offset = this.bb!.__offset(this.bb_pos, 10);
+  return offset ? (obj || new GameView()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+}
+
 static startGameOverEvent(builder:flatbuffers.Builder) {
-  builder.startObject(3);
+  builder.startObject(4);
 }
 
 static addGameId(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset) {
@@ -57,16 +65,13 @@ static addScoreLine(builder:flatbuffers.Builder, scoreLineOffset:flatbuffers.Off
   builder.addFieldOffset(2, scoreLineOffset, 0);
 }
 
+static addGame(builder:flatbuffers.Builder, gameOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(3, gameOffset, 0);
+}
+
 static endGameOverEvent(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createGameOverEvent(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset, resultOffset:flatbuffers.Offset, scoreLineOffset:flatbuffers.Offset):flatbuffers.Offset {
-  GameOverEvent.startGameOverEvent(builder);
-  GameOverEvent.addGameId(builder, gameIdOffset);
-  GameOverEvent.addResult(builder, resultOffset);
-  GameOverEvent.addScoreLine(builder, scoreLineOffset);
-  return GameOverEvent.endGameOverEvent(builder);
-}
 }

ui/src/gen/fbs/scrabblefb/match-found-event.ts

@@ -2,6 +2,9 @@
 
 import * as flatbuffers from 'flatbuffers';
 
+import { StateView } from '../scrabblefb/state-view.js';
+
+
 export class MatchFoundEvent {
   bb: flatbuffers.ByteBuffer|null = null;
   bb_pos = 0;
@@ -27,22 +30,26 @@ gameId(optionalEncoding?:any):string|Uint8Array|null {
   return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
 }
 
+state(obj?:StateView):StateView|null {
+  const offset = this.bb!.__offset(this.bb_pos, 6);
+  return offset ? (obj || new StateView()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+}
+
 static startMatchFoundEvent(builder:flatbuffers.Builder) {
-  builder.startObject(1);
+  builder.startObject(2);
 }
 
 static addGameId(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset) {
   builder.addFieldOffset(0, gameIdOffset, 0);
 }
 
+static addState(builder:flatbuffers.Builder, stateOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(1, stateOffset, 0);
+}
+
 static endMatchFoundEvent(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createMatchFoundEvent(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset):flatbuffers.Offset {
-  MatchFoundEvent.startMatchFoundEvent(builder);
-  MatchFoundEvent.addGameId(builder, gameIdOffset);
-  return MatchFoundEvent.endMatchFoundEvent(builder);
-}
 }

ui/src/gen/fbs/scrabblefb/move-result.ts

@@ -34,8 +34,28 @@ game(obj?:GameView):GameView|null {
   return offset ? (obj || new GameView()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
 }
 
+rack(index: number):number|null {
+  const offset = this.bb!.__offset(this.bb_pos, 8);
+  return offset ? this.bb!.readUint8(this.bb!.__vector(this.bb_pos + offset) + index) : 0;
+}
+
+rackLength():number {
+  const offset = this.bb!.__offset(this.bb_pos, 8);
+  return offset ? this.bb!.__vector_len(this.bb_pos + offset) : 0;
+}
+
+rackArray():Uint8Array|null {
+  const offset = this.bb!.__offset(this.bb_pos, 8);
+  return offset ? new Uint8Array(this.bb!.bytes().buffer, this.bb!.bytes().byteOffset + this.bb!.__vector(this.bb_pos + offset), this.bb!.__vector_len(this.bb_pos + offset)) : null;
+}
+
+bagLen():number {
+  const offset = this.bb!.__offset(this.bb_pos, 10);
+  return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
+}
+
 static startMoveResult(builder:flatbuffers.Builder) {
-  builder.startObject(2);
+  builder.startObject(4);
 }
 
 static addMove(builder:flatbuffers.Builder, moveOffset:flatbuffers.Offset) {
@@ -46,6 +66,26 @@ static addGame(builder:flatbuffers.Builder, gameOffset:flatbuffers.Offset) {
   builder.addFieldOffset(1, gameOffset, 0);
 }
 
+static addRack(builder:flatbuffers.Builder, rackOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(2, rackOffset, 0);
+}
+
+static createRackVector(builder:flatbuffers.Builder, data:number[]|Uint8Array):flatbuffers.Offset {
+  builder.startVector(1, data.length, 1);
+  for (let i = data.length - 1; i >= 0; i--) {
+    builder.addInt8(data[i]!);
+  }
+  return builder.endVector();
+}
+
+static startRackVector(builder:flatbuffers.Builder, numElems:number) {
+  builder.startVector(1, numElems, 1);
+}
+
+static addBagLen(builder:flatbuffers.Builder, bagLen:number) {
+  builder.addFieldInt32(3, bagLen, 0);
+}
+
 static endMoveResult(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;

ui/src/gen/fbs/scrabblefb/notification-event.ts

@@ -2,6 +2,11 @@
 
 import * as flatbuffers from 'flatbuffers';
 
+import { AccountRef } from '../scrabblefb/account-ref.js';
+import { Invitation } from '../scrabblefb/invitation.js';
+import { StateView } from '../scrabblefb/state-view.js';
+
+
 export class NotificationEvent {
   bb: flatbuffers.ByteBuffer|null = null;
   bb_pos = 0;
@@ -27,22 +32,44 @@ kind(optionalEncoding?:any):string|Uint8Array|null {
   return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
 }
 
+account(obj?:AccountRef):AccountRef|null {
+  const offset = this.bb!.__offset(this.bb_pos, 6);
+  return offset ? (obj || new AccountRef()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+}
+
+invitation(obj?:Invitation):Invitation|null {
+  const offset = this.bb!.__offset(this.bb_pos, 8);
+  return offset ? (obj || new Invitation()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+}
+
+state(obj?:StateView):StateView|null {
+  const offset = this.bb!.__offset(this.bb_pos, 10);
+  return offset ? (obj || new StateView()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+}
+
 static startNotificationEvent(builder:flatbuffers.Builder) {
-  builder.startObject(1);
+  builder.startObject(4);
 }
 
 static addKind(builder:flatbuffers.Builder, kindOffset:flatbuffers.Offset) {
   builder.addFieldOffset(0, kindOffset, 0);
 }
 
+static addAccount(builder:flatbuffers.Builder, accountOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(1, accountOffset, 0);
+}
+
+static addInvitation(builder:flatbuffers.Builder, invitationOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(2, invitationOffset, 0);
+}
+
+static addState(builder:flatbuffers.Builder, stateOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(3, stateOffset, 0);
+}
+
 static endNotificationEvent(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createNotificationEvent(builder:flatbuffers.Builder, kindOffset:flatbuffers.Offset):flatbuffers.Offset {
-  NotificationEvent.startNotificationEvent(builder);
-  NotificationEvent.addKind(builder, kindOffset);
-  return NotificationEvent.endNotificationEvent(builder);
-}
 }

ui/src/gen/fbs/scrabblefb/opponent-moved-event.ts

@@ -2,6 +2,10 @@
 
 import * as flatbuffers from 'flatbuffers';
 
+import { GameView } from '../scrabblefb/game-view.js';
+import { MoveRecord } from '../scrabblefb/move-record.js';
+
+
 export class OpponentMovedEvent {
   bb: flatbuffers.ByteBuffer|null = null;
   bb_pos = 0;
@@ -49,8 +53,23 @@ total():number {
   return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
 }
 
+move(obj?:MoveRecord):MoveRecord|null {
+  const offset = this.bb!.__offset(this.bb_pos, 14);
+  return offset ? (obj || new MoveRecord()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+}
+
+game(obj?:GameView):GameView|null {
+  const offset = this.bb!.__offset(this.bb_pos, 16);
+  return offset ? (obj || new GameView()).__init(this.bb!.__indirect(this.bb_pos + offset), this.bb!) : null;
+}
+
+bagLen():number {
+  const offset = this.bb!.__offset(this.bb_pos, 18);
+  return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
+}
+
 static startOpponentMovedEvent(builder:flatbuffers.Builder) {
-  builder.startObject(5);
+  builder.startObject(8);
 }
 
 static addGameId(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset) {
@@ -73,18 +92,21 @@ static addTotal(builder:flatbuffers.Builder, total:number) {
   builder.addFieldInt32(4, total, 0);
 }
 
+static addMove(builder:flatbuffers.Builder, moveOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(5, moveOffset, 0);
+}
+
+static addGame(builder:flatbuffers.Builder, gameOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(6, gameOffset, 0);
+}
+
+static addBagLen(builder:flatbuffers.Builder, bagLen:number) {
+  builder.addFieldInt32(7, bagLen, 0);
+}
+
 static endOpponentMovedEvent(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createOpponentMovedEvent(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset, seat:number, actionOffset:flatbuffers.Offset, score:number, total:number):flatbuffers.Offset {
-  OpponentMovedEvent.startOpponentMovedEvent(builder);
-  OpponentMovedEvent.addGameId(builder, gameIdOffset);
-  OpponentMovedEvent.addSeat(builder, seat);
-  OpponentMovedEvent.addAction(builder, actionOffset);
-  OpponentMovedEvent.addScore(builder, score);
-  OpponentMovedEvent.addTotal(builder, total);
-  return OpponentMovedEvent.endOpponentMovedEvent(builder);
-}
 }

ui/src/gen/fbs/scrabblefb/your-turn-event.ts

@@ -60,8 +60,13 @@ scoreLine(optionalEncoding?:any):string|Uint8Array|null {
   return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
 }
 
+moveCount():number {
+  const offset = this.bb!.__offset(this.bb_pos, 16);
+  return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
+}
+
 static startYourTurnEvent(builder:flatbuffers.Builder) {
-  builder.startObject(6);
+  builder.startObject(7);
 }
 
 static addGameId(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset) {
@@ -88,12 +93,16 @@ static addScoreLine(builder:flatbuffers.Builder, scoreLineOffset:flatbuffers.Off
   builder.addFieldOffset(5, scoreLineOffset, 0);
 }
 
+static addMoveCount(builder:flatbuffers.Builder, moveCount:number) {
+  builder.addFieldInt32(6, moveCount, 0);
+}
+
 static endYourTurnEvent(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createYourTurnEvent(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset, deadlineUnix:bigint, opponentNameOffset:flatbuffers.Offset, lastActionOffset:flatbuffers.Offset, lastWordOffset:flatbuffers.Offset, scoreLineOffset:flatbuffers.Offset):flatbuffers.Offset {
+static createYourTurnEvent(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset, deadlineUnix:bigint, opponentNameOffset:flatbuffers.Offset, lastActionOffset:flatbuffers.Offset, lastWordOffset:flatbuffers.Offset, scoreLineOffset:flatbuffers.Offset, moveCount:number):flatbuffers.Offset {
   YourTurnEvent.startYourTurnEvent(builder);
   YourTurnEvent.addGameId(builder, gameIdOffset);
   YourTurnEvent.addDeadlineUnix(builder, deadlineUnix);
@@ -101,6 +110,7 @@ static createYourTurnEvent(builder:flatbuffers.Builder, gameIdOffset:flatbuffers
   YourTurnEvent.addLastAction(builder, lastActionOffset);
   YourTurnEvent.addLastWord(builder, lastWordOffset);
   YourTurnEvent.addScoreLine(builder, scoreLineOffset);
+  YourTurnEvent.addMoveCount(builder, moveCount);
   return YourTurnEvent.endYourTurnEvent(builder);
 }
 }