Stage 17 round 5 — backend/correctness bug fixes

- Resign on the opponent's turn: engine ResignSeat(seat) resigns a specific seat
  (not just toMove); game.Resign bypasses the turn check and forfeits the actor's seat.
- Quick-match cancel was a UI no-op (only stopped polling): add the full path
  (REST /lobby/cancel -> gateway lobby.cancel -> client) and clear the matchmaker's
  pending result on Cancel, so a cancelled search is dequeued (no 'already queued', no
  later robot-substituted game). NewGame dequeues on cancel and on abandon.
- Lobby win/loss: result.ts ranked by score, so a 0-0 resignation read as a win.
  The winner now takes rank 1 and the viewer is placed from rank 2 — matching the
  game-detail screen.
- Friend request to a robot: robots no longer block requests; the request stays
  pending and expires (friendRequestTTL), mirroring a human who ignores it.
- Nudge cooldown: ErrNudgeTooSoon now maps to a distinct nudge_too_soon code with a
  correct message; the chat nudge button disables during the hourly cooldown; the
  nudge note reads 'Waiting for your move!' (button keeps the Nudge action label).
Tests: engine/service off-turn resign, matchmaker cancel-clears-result, friend-to-robot
inttest, result.ts 0-0 resignation, nudge_too_soon mapping.

backend/internal/account/account.go

@@ -112,17 +112,19 @@ func (s *Store) ProvisionByIdentity(ctx context.Context, kind, externalID string
 }
 
 // ProvisionRobot provisions (or finds) the durable account backing a robot pool
-// member: a KindRobot identity carrying displayName, with chat and friend requests
-// blocked so the robot never engages socially. Robot names are system-generated, not
-// player-edited, so they bypass the editable display-name validation and may carry
-// forms the editor rejects (an abbreviated surname like "Peter J."). It is idempotent:
-// repeated calls converge the display name and both block flags.
+// member: a KindRobot identity carrying displayName, with chat blocked but friend
+// requests NOT blocked — a request to a robot is accepted as pending and, since the
+// robot never responds, simply expires (friendRequestTTL), exactly mirroring a human
+// who ignores the request. Robot names are system-generated, not player-edited, so they
+// bypass the editable display-name validation and may carry forms the editor rejects (an
+// abbreviated surname like "Peter J."). It is idempotent: repeated calls converge the
+// display name and both block flags.
 func (s *Store) ProvisionRobot(ctx context.Context, externalID, displayName string) (Account, error) {
 	acc, err := s.provision(ctx, KindRobot, externalID, provisionSeed{displayName: displayName})
 	if err != nil {
 		return Account{}, err
 	}
-	if acc.DisplayName == displayName && acc.BlockChat && acc.BlockFriendRequests {
+	if acc.DisplayName == displayName && acc.BlockChat && !acc.BlockFriendRequests {
 		return acc, nil
 	}
 	stmt := table.Accounts.UPDATE(
@@ -130,7 +132,7 @@ func (s *Store) ProvisionRobot(ctx context.Context, externalID, displayName stri
 		table.Accounts.BlockFriendRequests, table.Accounts.UpdatedAt,
 	).SET(
 		postgres.String(displayName), postgres.Bool(true),
-		postgres.Bool(true), postgres.TimestampzT(time.Now().UTC()),
+		postgres.Bool(false), postgres.TimestampzT(time.Now().UTC()),
 	).WHERE(table.Accounts.AccountID.EQ(postgres.UUID(acc.ID))).
 		RETURNING(table.Accounts.AllColumns)