feat: implement full restore functionality with TUI integration

- Add complete restore engine (internal/restore/)
  - RestoreSingle() for single database restore
  - RestoreCluster() for full cluster restore
  - Archive format detection (7 formats supported)
  - Safety validation (integrity, disk space, tools)
  - Streaming decompression with pigz support

- Add CLI restore commands (cmd/restore.go)
  - restore single: restore single database backup
  - restore cluster: restore full cluster backup
  - restore list: list available backup archives
  - Safety-first design: dry-run by default, --confirm required

- Add TUI restore integration (internal/tui/)
  - Archive browser: browse and select backups
  - Restore preview: safety checks and confirmation
  - Restore execution: real-time progress tracking
  - Backup manager: comprehensive archive management

- Features:
  - Format auto-detection (.dump, .dump.gz, .sql, .sql.gz, .tar.gz)
  - Archive validation before restore
  - Disk space verification
  - Tool availability checks
  - Target database configuration
  - Clean-first and create-if-missing options
  - Parallel decompression support
  - Progress tracking with phases

Phase 1 (Core Functionality) complete and tested

internal/restore/formats.go

@@ -0,0 +1,110 @@
+package restore
+
+import (
+	"strings"
+)
+
+// ArchiveFormat represents the type of backup archive
+type ArchiveFormat string
+
+const (
+	FormatPostgreSQLDump   ArchiveFormat = "PostgreSQL Dump (.dump)"
+	FormatPostgreSQLDumpGz ArchiveFormat = "PostgreSQL Dump Compressed (.dump.gz)"
+	FormatPostgreSQLSQL    ArchiveFormat = "PostgreSQL SQL (.sql)"
+	FormatPostgreSQLSQLGz  ArchiveFormat = "PostgreSQL SQL Compressed (.sql.gz)"
+	FormatMySQLSQL         ArchiveFormat = "MySQL SQL (.sql)"
+	FormatMySQLSQLGz       ArchiveFormat = "MySQL SQL Compressed (.sql.gz)"
+	FormatClusterTarGz     ArchiveFormat = "Cluster Archive (.tar.gz)"
+	FormatUnknown          ArchiveFormat = "Unknown"
+)
+
+// DetectArchiveFormat detects the format of a backup archive from its filename
+func DetectArchiveFormat(filename string) ArchiveFormat {
+	lower := strings.ToLower(filename)
+
+	// Check for cluster archives first (most specific)
+	if strings.Contains(lower, "cluster") && strings.HasSuffix(lower, ".tar.gz") {
+		return FormatClusterTarGz
+	}
+
+	// Check for compressed formats
+	if strings.HasSuffix(lower, ".dump.gz") {
+		return FormatPostgreSQLDumpGz
+	}
+
+	if strings.HasSuffix(lower, ".sql.gz") {
+		// Determine if MySQL or PostgreSQL based on naming convention
+		if strings.Contains(lower, "mysql") || strings.Contains(lower, "mariadb") {
+			return FormatMySQLSQLGz
+		}
+		return FormatPostgreSQLSQLGz
+	}
+
+	// Check for uncompressed formats
+	if strings.HasSuffix(lower, ".dump") {
+		return FormatPostgreSQLDump
+	}
+
+	if strings.HasSuffix(lower, ".sql") {
+		// Determine if MySQL or PostgreSQL based on naming convention
+		if strings.Contains(lower, "mysql") || strings.Contains(lower, "mariadb") {
+			return FormatMySQLSQL
+		}
+		return FormatPostgreSQLSQL
+	}
+
+	if strings.HasSuffix(lower, ".tar.gz") || strings.HasSuffix(lower, ".tgz") {
+		return FormatClusterTarGz
+	}
+
+	return FormatUnknown
+}
+
+// IsCompressed returns true if the archive format is compressed
+func (f ArchiveFormat) IsCompressed() bool {
+	return f == FormatPostgreSQLDumpGz ||
+		f == FormatPostgreSQLSQLGz ||
+		f == FormatMySQLSQLGz ||
+		f == FormatClusterTarGz
+}
+
+// IsClusterBackup returns true if the archive is a cluster backup
+func (f ArchiveFormat) IsClusterBackup() bool {
+	return f == FormatClusterTarGz
+}
+
+// IsPostgreSQL returns true if the archive is PostgreSQL format
+func (f ArchiveFormat) IsPostgreSQL() bool {
+	return f == FormatPostgreSQLDump ||
+		f == FormatPostgreSQLDumpGz ||
+		f == FormatPostgreSQLSQL ||
+		f == FormatPostgreSQLSQLGz ||
+		f == FormatClusterTarGz
+}
+
+// IsMySQL returns true if format is MySQL
+func (f ArchiveFormat) IsMySQL() bool {
+	return f == FormatMySQLSQL || f == FormatMySQLSQLGz
+}
+
+// String returns human-readable format name
+func (f ArchiveFormat) String() string {
+	switch f {
+	case FormatPostgreSQLDump:
+		return "PostgreSQL Dump"
+	case FormatPostgreSQLDumpGz:
+		return "PostgreSQL Dump (gzip)"
+	case FormatPostgreSQLSQL:
+		return "PostgreSQL SQL"
+	case FormatPostgreSQLSQLGz:
+		return "PostgreSQL SQL (gzip)"
+	case FormatMySQLSQL:
+		return "MySQL SQL"
+	case FormatMySQLSQLGz:
+		return "MySQL SQL (gzip)"
+	case FormatClusterTarGz:
+		return "Cluster Archive (tar.gz)"
+	default:
+		return "Unknown"
+	}
+}