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.

pkg/fbs/scrabblefb/GameOverEvent.go

@@ -65,8 +65,21 @@ func (rcv *GameOverEvent) ScoreLine() []byte {
 	return nil
 }
 
+func (rcv *GameOverEvent) Game(obj *GameView) *GameView {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(10))
+	if o != 0 {
+		x := rcv._tab.Indirect(o + rcv._tab.Pos)
+		if obj == nil {
+			obj = new(GameView)
+		}
+		obj.Init(rcv._tab.Bytes, x)
+		return obj
+	}
+	return nil
+}
+
 func GameOverEventStart(builder *flatbuffers.Builder) {
-	builder.StartObject(3)
+	builder.StartObject(4)
 }
 func GameOverEventAddGameId(builder *flatbuffers.Builder, gameId flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(gameId), 0)
@@ -77,6 +90,9 @@ func GameOverEventAddResult(builder *flatbuffers.Builder, result flatbuffers.UOf
 func GameOverEventAddScoreLine(builder *flatbuffers.Builder, scoreLine flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(2, flatbuffers.UOffsetT(scoreLine), 0)
 }
+func GameOverEventAddGame(builder *flatbuffers.Builder, game flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(3, flatbuffers.UOffsetT(game), 0)
+}
 func GameOverEventEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/fbs/scrabblefb/MatchFoundEvent.go

@@ -49,12 +49,28 @@ func (rcv *MatchFoundEvent) GameId() []byte {
 	return nil
 }
 
+func (rcv *MatchFoundEvent) State(obj *StateView) *StateView {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(6))
+	if o != 0 {
+		x := rcv._tab.Indirect(o + rcv._tab.Pos)
+		if obj == nil {
+			obj = new(StateView)
+		}
+		obj.Init(rcv._tab.Bytes, x)
+		return obj
+	}
+	return nil
+}
+
 func MatchFoundEventStart(builder *flatbuffers.Builder) {
-	builder.StartObject(1)
+	builder.StartObject(2)
 }
 func MatchFoundEventAddGameId(builder *flatbuffers.Builder, gameId flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(gameId), 0)
 }
+func MatchFoundEventAddState(builder *flatbuffers.Builder, state flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(1, flatbuffers.UOffsetT(state), 0)
+}
 func MatchFoundEventEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/fbs/scrabblefb/MoveResult.go

@@ -67,8 +67,54 @@ func (rcv *MoveResult) Game(obj *GameView) *GameView {
 	return nil
 }
 
+func (rcv *MoveResult) Rack(j int) byte {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(8))
+	if o != 0 {
+		a := rcv._tab.Vector(o)
+		return rcv._tab.GetByte(a + flatbuffers.UOffsetT(j*1))
+	}
+	return 0
+}
+
+func (rcv *MoveResult) RackLength() int {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(8))
+	if o != 0 {
+		return rcv._tab.VectorLen(o)
+	}
+	return 0
+}
+
+func (rcv *MoveResult) RackBytes() []byte {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(8))
+	if o != 0 {
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
+	}
+	return nil
+}
+
+func (rcv *MoveResult) MutateRack(j int, n byte) bool {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(8))
+	if o != 0 {
+		a := rcv._tab.Vector(o)
+		return rcv._tab.MutateByte(a+flatbuffers.UOffsetT(j*1), n)
+	}
+	return false
+}
+
+func (rcv *MoveResult) BagLen() int32 {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(10))
+	if o != 0 {
+		return rcv._tab.GetInt32(o + rcv._tab.Pos)
+	}
+	return 0
+}
+
+func (rcv *MoveResult) MutateBagLen(n int32) bool {
+	return rcv._tab.MutateInt32Slot(10, n)
+}
+
 func MoveResultStart(builder *flatbuffers.Builder) {
-	builder.StartObject(2)
+	builder.StartObject(4)
 }
 func MoveResultAddMove(builder *flatbuffers.Builder, move flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(move), 0)
@@ -76,6 +122,15 @@ func MoveResultAddMove(builder *flatbuffers.Builder, move flatbuffers.UOffsetT)
 func MoveResultAddGame(builder *flatbuffers.Builder, game flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(1, flatbuffers.UOffsetT(game), 0)
 }
+func MoveResultAddRack(builder *flatbuffers.Builder, rack flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(2, flatbuffers.UOffsetT(rack), 0)
+}
+func MoveResultStartRackVector(builder *flatbuffers.Builder, numElems int) flatbuffers.UOffsetT {
+	return builder.StartVector(1, numElems, 1)
+}
+func MoveResultAddBagLen(builder *flatbuffers.Builder, bagLen int32) {
+	builder.PrependInt32Slot(3, bagLen, 0)
+}
 func MoveResultEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/fbs/scrabblefb/NotificationEvent.go

@@ -49,12 +49,60 @@ func (rcv *NotificationEvent) Kind() []byte {
 	return nil
 }
 
+func (rcv *NotificationEvent) Account(obj *AccountRef) *AccountRef {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(6))
+	if o != 0 {
+		x := rcv._tab.Indirect(o + rcv._tab.Pos)
+		if obj == nil {
+			obj = new(AccountRef)
+		}
+		obj.Init(rcv._tab.Bytes, x)
+		return obj
+	}
+	return nil
+}
+
+func (rcv *NotificationEvent) Invitation(obj *Invitation) *Invitation {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(8))
+	if o != 0 {
+		x := rcv._tab.Indirect(o + rcv._tab.Pos)
+		if obj == nil {
+			obj = new(Invitation)
+		}
+		obj.Init(rcv._tab.Bytes, x)
+		return obj
+	}
+	return nil
+}
+
+func (rcv *NotificationEvent) State(obj *StateView) *StateView {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(10))
+	if o != 0 {
+		x := rcv._tab.Indirect(o + rcv._tab.Pos)
+		if obj == nil {
+			obj = new(StateView)
+		}
+		obj.Init(rcv._tab.Bytes, x)
+		return obj
+	}
+	return nil
+}
+
 func NotificationEventStart(builder *flatbuffers.Builder) {
-	builder.StartObject(1)
+	builder.StartObject(4)
 }
 func NotificationEventAddKind(builder *flatbuffers.Builder, kind flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(kind), 0)
 }
+func NotificationEventAddAccount(builder *flatbuffers.Builder, account flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(1, flatbuffers.UOffsetT(account), 0)
+}
+func NotificationEventAddInvitation(builder *flatbuffers.Builder, invitation flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(2, flatbuffers.UOffsetT(invitation), 0)
+}
+func NotificationEventAddState(builder *flatbuffers.Builder, state flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(3, flatbuffers.UOffsetT(state), 0)
+}
 func NotificationEventEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/fbs/scrabblefb/OpponentMovedEvent.go

@@ -93,8 +93,46 @@ func (rcv *OpponentMovedEvent) MutateTotal(n int32) bool {
 	return rcv._tab.MutateInt32Slot(12, n)
 }
 
+func (rcv *OpponentMovedEvent) Move(obj *MoveRecord) *MoveRecord {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(14))
+	if o != 0 {
+		x := rcv._tab.Indirect(o + rcv._tab.Pos)
+		if obj == nil {
+			obj = new(MoveRecord)
+		}
+		obj.Init(rcv._tab.Bytes, x)
+		return obj
+	}
+	return nil
+}
+
+func (rcv *OpponentMovedEvent) Game(obj *GameView) *GameView {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(16))
+	if o != 0 {
+		x := rcv._tab.Indirect(o + rcv._tab.Pos)
+		if obj == nil {
+			obj = new(GameView)
+		}
+		obj.Init(rcv._tab.Bytes, x)
+		return obj
+	}
+	return nil
+}
+
+func (rcv *OpponentMovedEvent) BagLen() int32 {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(18))
+	if o != 0 {
+		return rcv._tab.GetInt32(o + rcv._tab.Pos)
+	}
+	return 0
+}
+
+func (rcv *OpponentMovedEvent) MutateBagLen(n int32) bool {
+	return rcv._tab.MutateInt32Slot(18, n)
+}
+
 func OpponentMovedEventStart(builder *flatbuffers.Builder) {
-	builder.StartObject(5)
+	builder.StartObject(8)
 }
 func OpponentMovedEventAddGameId(builder *flatbuffers.Builder, gameId flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(gameId), 0)
@@ -111,6 +149,15 @@ func OpponentMovedEventAddScore(builder *flatbuffers.Builder, score int32) {
 func OpponentMovedEventAddTotal(builder *flatbuffers.Builder, total int32) {
 	builder.PrependInt32Slot(4, total, 0)
 }
+func OpponentMovedEventAddMove(builder *flatbuffers.Builder, move flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(5, flatbuffers.UOffsetT(move), 0)
+}
+func OpponentMovedEventAddGame(builder *flatbuffers.Builder, game flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(6, flatbuffers.UOffsetT(game), 0)
+}
+func OpponentMovedEventAddBagLen(builder *flatbuffers.Builder, bagLen int32) {
+	builder.PrependInt32Slot(7, bagLen, 0)
+}
 func OpponentMovedEventEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/fbs/scrabblefb/YourTurnEvent.go

@@ -93,8 +93,20 @@ func (rcv *YourTurnEvent) ScoreLine() []byte {
 	return nil
 }
 
+func (rcv *YourTurnEvent) MoveCount() int32 {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(16))
+	if o != 0 {
+		return rcv._tab.GetInt32(o + rcv._tab.Pos)
+	}
+	return 0
+}
+
+func (rcv *YourTurnEvent) MutateMoveCount(n int32) bool {
+	return rcv._tab.MutateInt32Slot(16, n)
+}
+
 func YourTurnEventStart(builder *flatbuffers.Builder) {
-	builder.StartObject(6)
+	builder.StartObject(7)
 }
 func YourTurnEventAddGameId(builder *flatbuffers.Builder, gameId flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(gameId), 0)
@@ -114,6 +126,9 @@ func YourTurnEventAddLastWord(builder *flatbuffers.Builder, lastWord flatbuffers
 func YourTurnEventAddScoreLine(builder *flatbuffers.Builder, scoreLine flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(5, flatbuffers.UOffsetT(scoreLine), 0)
 }
+func YourTurnEventAddMoveCount(builder *flatbuffers.Builder, moveCount int32) {
+	builder.PrependInt32Slot(6, moveCount, 0)
+}
 func YourTurnEventEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }