feat: bind signed rosters to assignments

server/store/assignment_sql_test.go

@@ -3,6 +3,8 @@ package store
 import (
 	"testing"
 	"time"
+
+	"github.com/cosmic-clash/cosmic-clash/server/domain"
 )
 
 func TestAssignmentSQLBindsPlayerAndPreservesIdenticalReplay(t *testing.T) {
@@ -37,4 +39,7 @@ func TestAssignmentStoreRejectsInvalidBatches(t *testing.T) {
 	if err := SaveAssignments(nil, nil, []DurableAssignment{{MatchID: "match-1", PlayerID: "player-1"}}); err == nil {
 		t.Fatal("invalid assignment batch accepted")
 	}
+	if err := SaveVerifiedAssignmentRoster(nil, nil, domain.Assignment{}, nil); err == nil {
+		t.Fatal("empty verified roster accepted")
+	}
 }