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/gormstore/config.go

@@ -0,0 +1,78 @@
+package gormstore
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/lukaszraczylo/gohoarder/pkg/errors"
+)
+
+// Config holds GORM store configuration
+type Config struct {
+	// Database connection
+	Driver string // "sqlite", "postgres", "mysql"
+	DSN    string // Data Source Name
+
+	// Connection pool
+	MaxOpenConns    int
+	MaxIdleConns    int
+	ConnMaxLifetime time.Duration
+
+	// GORM settings
+	LogLevel string // "silent", "error", "warn", "info"
+}
+
+// Validate validates the configuration
+func (c *Config) Validate() error {
+	if c.Driver == "" {
+		return errors.New(errors.ErrCodeInvalidConfig, "driver is required")
+	}
+	if c.DSN == "" {
+		return errors.New(errors.ErrCodeInvalidConfig, "DSN is required")
+	}
+
+	// Set defaults
+	if c.MaxOpenConns == 0 {
+		c.MaxOpenConns = 25
+	}
+	if c.MaxIdleConns == 0 {
+		c.MaxIdleConns = 5
+	}
+	if c.ConnMaxLifetime == 0 {
+		c.ConnMaxLifetime = time.Hour
+	}
+	if c.LogLevel == "" {
+		c.LogLevel = "warn"
+	}
+
+	return nil
+}
+
+// BuildPostgresDSN builds PostgreSQL DSN from structured config
+func BuildPostgresDSN(host string, port int, user, password, database, sslmode string) string {
+	if sslmode == "" {
+		sslmode = "disable"
+	}
+	return fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
+		host, port, user, password, database, sslmode)
+}
+
+// BuildMySQLDSN builds MySQL/MariaDB DSN from structured config
+func BuildMySQLDSN(host string, port int, user, password, database, charset string) string {
+	if charset == "" {
+		charset = "utf8mb4"
+	}
+	return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=%s&parseTime=True&loc=Local",
+		user, password, host, port, database, charset)
+}
+
+// BuildSQLiteDSN builds SQLite DSN with pragmas
+func BuildSQLiteDSN(path string, walMode bool) string {
+	if path == "" {
+		path = "gohoarder.db"
+	}
+	if walMode {
+		return fmt.Sprintf("%s?_journal_mode=WAL&_busy_timeout=5000&_synchronous=NORMAL&_cache_size=2000", path)
+	}
+	return fmt.Sprintf("%s?_journal_mode=DELETE&_busy_timeout=5000&_synchronous=NORMAL", path)
+}