feat: add brand library management features

- Introduced BrandLibrarySummary type to encapsulate brand library limits and usage.
- Updated Brand interface to include keyword_count and question_count fields.
- Implemented brand library limits in the backend, including max brands, keywords, and questions per keyword.
- Added API endpoint to retrieve brand library summary.
- Enhanced BrandsView.vue to display brand library usage and limits.
- Implemented computed properties to manage brand, keyword, and question limits in the UI.
- Updated mutation handlers to invalidate relevant queries upon creating/updating brands, keywords, and questions.
- Added visual indicators for brand, keyword, and question limits in the UI.
- Enhanced error handling for exceeding brand and keyword limits during creation.

server/internal/tenant/transport/router.go

@@ -80,6 +80,7 @@ func RegisterRoutes(app *bootstrap.App) {
 	brands := protected.Group("/tenant/brands")
 	brandHandler := NewBrandHandler(app)
 	brands.GET("", brandHandler.List)
+	brands.GET("/library-summary", brandHandler.Summary)
 	brands.POST("", brandHandler.Create)
 	brands.GET("/:id", brandHandler.Detail)
 	brands.PUT("/:id", brandHandler.Update)