fix(test): update tests for event bus + room-based Hub signatures

- integration_test: pass events.Bus to NewRouter
- handler_test: pass events.Bus to handler.New
- hub_test: add mock MembershipChecker, JWT token generation,
  replace hub.clients with totalClients() helper for room-based Hub

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/internal/handler/handler_test.go

@@ -13,6 +13,7 @@ import (
 
 	"github.com/go-chi/chi/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/multica-ai/multica/server/internal/events"
 	"github.com/multica-ai/multica/server/internal/realtime"
 	db "github.com/multica-ai/multica/server/pkg/db/generated"
 )
@@ -44,7 +45,8 @@ func TestMain(m *testing.M) {
 	queries := db.New(pool)
 	hub := realtime.NewHub()
 	go hub.Run()
-	testHandler = New(queries, pool, hub)
+	bus := events.NewBus()
+	testHandler = New(queries, pool, hub, bus)
 	testPool = pool
 
 	testUserID, testWorkspaceID, err = setupHandlerTestFixture(ctx, pool)