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/lib/model.ts

@@ -205,6 +205,22 @@ export interface AccountRef {
   displayName: string;
 }
 
+// RobotBlockEntry is one blocked disguised-robot opponent: a per-game record (not a real
+// account) carrying the game name the player saw and the game/seat it was blocked in. Its id
+// is used to unblock it.
+export interface RobotBlockEntry {
+  id: string;
+  displayName: string;
+  gameId: string;
+  seat: number;
+}
+
+// BlockList is the caller's blocked humans plus the per-game disguised-robot blocks.
+export interface BlockList {
+  blocked: AccountRef[];
+  robots: RobotBlockEntry[];
+}
+
 /** A freshly issued one-time friend code (the plaintext is returned once). */
 export interface FriendCode {
   code: string;