chore(schema): migrate to GORM V2 with multi-database support

- [x] Implement GORM V2 metadata store with SQLite, PostgreSQL, and MySQL support
- [x] Add database migration system using gormigrate for schema versioning
- [x] Create migration CLI tool with support for migrate, rollback, and status commands
- [x] Add Docker support for migration container (Dockerfile.migrate)
- [x] Implement automatic partition management for PostgreSQL time-series tables
- [x] Add background aggregation worker for download statistics
- [x] Support connection pooling configuration (max_open_conns, max_idle_conns, conn_max_lifetime)
- [x] Add blocking mechanism based on vulnerability thresholds in stats and handlers
- [x] Update Helm charts with migration init containers and multi-database configuration
- [x] Replace deprecated SQLite store with optimized GORM implementation
- [x] Add comprehensive integration tests for MySQL and PostgreSQL
- [x] Update frontend to display blocked packages and storage utilization
- [x] Add goreleaser configuration for migrate binary and container image
- [x] Update configuration examples with database backend options and recommendations

pkg/metadata/interface.go

@@ -143,13 +143,18 @@ const (
 
 // Stats represents metadata statistics
 type Stats struct {
-	LastUpdated        time.Time `json:"last_updated"`
-	Registry           string    `json:"registry"`
-	TotalPackages      int64     `json:"total_packages"`
-	TotalSize          int64     `json:"total_size"`
-	TotalDownloads     int64     `json:"total_downloads"`
-	ScannedPackages    int64     `json:"scanned_packages"`
-	VulnerablePackages int64     `json:"vulnerable_packages"`
+	LastUpdated             time.Time `json:"last_updated"`
+	Registry                string    `json:"registry"`
+	TotalPackages           int64     `json:"total_packages"`
+	TotalSize               int64     `json:"total_size"`
+	TotalDownloads          int64     `json:"total_downloads"`
+	ScannedPackages         int64     `json:"scanned_packages"`
+	VulnerablePackages      int64     `json:"vulnerable_packages"`
+	BlockedPackages         int64     `json:"blocked_packages"`
+	CriticalVulnerabilities int64     `json:"critical_vulnerabilities"`
+	HighVulnerabilities     int64     `json:"high_vulnerabilities"`
+	ModerateVulnerabilities int64     `json:"moderate_vulnerabilities"`
+	LowVulnerabilities      int64     `json:"low_vulnerabilities"`
 }
 
 // TimeSeriesDataPoint represents a single data point in time-series