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

ui/src/gen/fbs/scrabblefb/target-request.ts

@@ -27,22 +27,34 @@ accountId(optionalEncoding?:any):string|Uint8Array|null {
   return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
 }
 
+gameId():string|null
+gameId(optionalEncoding:flatbuffers.Encoding):string|Uint8Array|null
+gameId(optionalEncoding?:any):string|Uint8Array|null {
+  const offset = this.bb!.__offset(this.bb_pos, 6);
+  return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
+}
+
 static startTargetRequest(builder:flatbuffers.Builder) {
-  builder.startObject(1);
+  builder.startObject(2);
 }
 
 static addAccountId(builder:flatbuffers.Builder, accountIdOffset:flatbuffers.Offset) {
   builder.addFieldOffset(0, accountIdOffset, 0);
 }
 
+static addGameId(builder:flatbuffers.Builder, gameIdOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(1, gameIdOffset, 0);
+}
+
 static endTargetRequest(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createTargetRequest(builder:flatbuffers.Builder, accountIdOffset:flatbuffers.Offset):flatbuffers.Offset {
+static createTargetRequest(builder:flatbuffers.Builder, accountIdOffset:flatbuffers.Offset, gameIdOffset:flatbuffers.Offset):flatbuffers.Offset {
   TargetRequest.startTargetRequest(builder);
   TargetRequest.addAccountId(builder, accountIdOffset);
+  TargetRequest.addGameId(builder, gameIdOffset);
   return TargetRequest.endTargetRequest(builder);
 }
 }