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/shared/config/config.go

@@ -16,6 +16,7 @@ type Config struct {
 	RabbitMQ           RabbitMQConfig      `mapstructure:"rabbitmq"`
 	Scheduler          SchedulerConfig     `mapstructure:"scheduler"`
 	MonitoringWorkers  MonitoringConfig    `mapstructure:"monitoring_workers"`
+	BrandLibrary       BrandLibraryConfig  `mapstructure:"brand_library"`
 	Redis              RedisConfig         `mapstructure:"redis"`
 	Qdrant             QdrantConfig        `mapstructure:"qdrant"`
 	ObjectStorage      ObjectStorageConfig `mapstructure:"object_storage"`
@@ -103,6 +104,20 @@ type MonitoringConfig struct {
 	ProjectionRebuildConcurrency int `mapstructure:"projection_rebuild_concurrency"`
 }
 
+type BrandLibraryConfig struct {
+	FreeBrandLimit         int `mapstructure:"free_brand_limit"`
+	PaidBrandLimit         int `mapstructure:"paid_brand_limit"`
+	MaxKeywords            int `mapstructure:"max_keywords"`
+	MaxQuestionsPerKeyword int `mapstructure:"max_questions_per_keyword"`
+}
+
+func (c BrandLibraryConfig) BrandLimitForPlan(planCode string) int {
+	if strings.EqualFold(strings.TrimSpace(planCode), "free") {
+		return c.FreeBrandLimit
+	}
+	return c.PaidBrandLimit
+}
+
 type QdrantConfig struct {
 	URL        string        `mapstructure:"url"`
 	APIKey     string        `mapstructure:"api_key"`
@@ -196,6 +211,7 @@ func Load(configPath string) (*Config, error) {
 	normalizeRabbitMQConfig(&cfg.RabbitMQ)
 	normalizeSchedulerConfig(&cfg.Scheduler)
 	normalizeMonitoringConfig(&cfg.MonitoringWorkers)
+	normalizeBrandLibraryConfig(&cfg.BrandLibrary)
 
 	return &cfg, nil
 }
@@ -398,6 +414,25 @@ func normalizeMonitoringConfig(cfg *MonitoringConfig) {
 	}
 }
 
+func normalizeBrandLibraryConfig(cfg *BrandLibraryConfig) {
+	if cfg == nil {
+		return
+	}
+
+	if cfg.FreeBrandLimit <= 0 {
+		cfg.FreeBrandLimit = 1
+	}
+	if cfg.PaidBrandLimit <= 0 {
+		cfg.PaidBrandLimit = 2
+	}
+	if cfg.MaxKeywords <= 0 {
+		cfg.MaxKeywords = 5
+	}
+	if cfg.MaxQuestionsPerKeyword <= 0 {
+		cfg.MaxQuestionsPerKeyword = 5
+	}
+}
+
 func lookupFirstNonEmptyEnv(keys ...string) (string, bool) {
 	for _, key := range keys {
 		if value, ok := lookupNonEmptyEnv(key); ok {

server/internal/shared/config/config_test.go

@@ -89,6 +89,30 @@ retrieval:
 	}
 }
 
+func TestLoadAppliesBrandLibraryDefaults(t *testing.T) {
+	configPath := writeTestConfig(t, `
+brand_library: {}
+`)
+
+	cfg, err := Load(configPath)
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+
+	if cfg.BrandLibrary.FreeBrandLimit != 1 {
+		t.Fatalf("expected default free brand limit 1, got %d", cfg.BrandLibrary.FreeBrandLimit)
+	}
+	if cfg.BrandLibrary.PaidBrandLimit != 2 {
+		t.Fatalf("expected default paid brand limit 2, got %d", cfg.BrandLibrary.PaidBrandLimit)
+	}
+	if cfg.BrandLibrary.MaxKeywords != 5 {
+		t.Fatalf("expected default max keywords 5, got %d", cfg.BrandLibrary.MaxKeywords)
+	}
+	if cfg.BrandLibrary.MaxQuestionsPerKeyword != 5 {
+		t.Fatalf("expected default max questions per keyword 5, got %d", cfg.BrandLibrary.MaxQuestionsPerKeyword)
+	}
+}
+
 func writeTestConfig(t *testing.T, body string) string {
 	t.Helper()