fix(social): robot blocks

Blocking an auto-match opponent who is secretly a pooled robot is recorded  instead in a separate `robot_blocks` table.

Now blocking behaves the same in that game (struck name, hidden composer) and lists the blocked opponent under the name you saw, but is recorded only against that game — the disguise holds, the shared robot is never globally blocked, and the matchmaker keeps pairing you with robots (so you can never block yourself out of opponents).

- the shared robot account is never put in `blocks`
- the matchmaker keeps it free and it is not blocked under its other per-game names
- the blocked list and the in-game card still show it by joining that table; an unblock deletes the row

gateway/internal/transcode/encode_social.go

@@ -60,12 +60,35 @@ func encodeOutgoingList(r backendclient.OutgoingListResp) []byte {
 	return b.FinishedBytes()
 }
 
+// buildRobotBlockVector builds the BlockList robots vector (per-game disguised-robot blocks).
+func buildRobotBlockVector(b *flatbuffers.Builder, robots []backendclient.RobotBlockResp) flatbuffers.UOffsetT {
+	offs := make([]flatbuffers.UOffsetT, len(robots))
+	for i, r := range robots {
+		id := b.CreateString(r.ID)
+		name := b.CreateString(r.DisplayName)
+		gid := b.CreateString(r.GameID)
+		fb.RobotBlockRefStart(b)
+		fb.RobotBlockRefAddId(b, id)
+		fb.RobotBlockRefAddDisplayName(b, name)
+		fb.RobotBlockRefAddGameId(b, gid)
+		fb.RobotBlockRefAddSeat(b, int32(r.Seat))
+		offs[i] = fb.RobotBlockRefEnd(b)
+	}
+	fb.BlockListStartRobotsVector(b, len(offs))
+	for i := len(offs) - 1; i >= 0; i-- {
+		b.PrependUOffsetT(offs[i])
+	}
+	return b.EndVector(len(offs))
+}
+
 // encodeBlockList builds a BlockList payload.
 func encodeBlockList(r backendclient.BlockListResp) []byte {
 	b := flatbuffers.NewBuilder(256)
 	v := buildAccountRefVector(b, r.Blocked, fb.BlockListStartBlockedVector)
+	rv := buildRobotBlockVector(b, r.Robots)
 	fb.BlockListStart(b)
 	fb.BlockListAddBlocked(b, v)
+	fb.BlockListAddRobots(b, rv)
 	b.Finish(fb.BlockListEnd(b))
 	return b.FinishedBytes()
 }

gateway/internal/transcode/transcode_social.go

@@ -166,7 +166,9 @@ func blocksListHandler(backend *backendclient.Client) Handler {
 func blockAddHandler(backend *backendclient.Client) Handler {
 	return func(ctx context.Context, req Request) ([]byte, error) {
 		in := fb.GetRootAsTargetRequest(req.Payload, 0)
-		if err := backend.Block(ctx, req.UserID, string(in.AccountId())); err != nil {
+		// game_id is set only by an in-game block, so a disguised-robot opponent is recorded
+		// per-game; it is empty for a settings-screen block.
+		if err := backend.Block(ctx, req.UserID, string(in.AccountId()), string(in.GameId())); err != nil {
 			return nil, err
 		}
 		return encodeAck(true), nil