feat: v2.0 Sprint 3 - Cloud URI Support & Command Integration (Part 1)

Sprint 3 Implementation - Cloud URI Support:

New Features:
✅ Cloud URI parser (s3://bucket/path)
✅ Backup command with --cloud URI flag
✅ Restore from cloud URIs
✅ Verify cloud backups
✅ Cleanup cloud storage with retention policy

New Files:
- internal/cloud/uri.go - Cloud URI parser
- internal/restore/ - Cloud download module
- internal/restore/cloud_download.go - Download & verify helper

Modified Commands:
- cmd/backup.go - Added --cloud s3://bucket/path flag
- cmd/restore.go - Auto-detect & download from cloud URIs
- cmd/verify.go - Verify backups from cloud storage
- cmd/cleanup.go - Apply retention policy to cloud storage

URI Support:
- s3://bucket/path/file.dump - AWS S3
- minio://bucket/path/file.dump - MinIO
- b2://bucket/path/file.dump - Backblaze B2
- gs://bucket/path/file.dump - Google Cloud Storage

Examples:
  # Backup with cloud URI
  dbbackup backup single mydb --cloud s3://my-bucket/backups/

  # Restore from cloud
  dbbackup restore single s3://my-bucket/backups/mydb.dump --confirm

  # Verify cloud backup
  dbbackup verify-backup s3://my-bucket/backups/mydb.dump

  # Cleanup old cloud backups
  dbbackup cleanup s3://my-bucket/backups/ --retention-days 30

Features:
- Automatic download to temp directory
- SHA-256 verification after download
- Automatic temp file cleanup
- Progress tracking for downloads
- Metadata synchronization
- Retention policy for cloud storage

Sprint 3 Part 1 COMPLETE!

cmd/verify.go

@@ -1,13 +1,16 @@
 package cmd
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
 	"time"
 
+	"dbbackup/internal/cloud"
 	"dbbackup/internal/metadata"
+	"dbbackup/internal/restore"
 	"dbbackup/internal/verification"
 	"github.com/spf13/cobra"
 )
@@ -46,7 +49,21 @@ func init() {
 }
 
 func runVerifyBackup(cmd *cobra.Command, args []string) error {
-	// Expand glob patterns
+	// Check if any argument is a cloud URI
+	hasCloudURI := false
+	for _, arg := range args {
+		if isCloudURI(arg) {
+			hasCloudURI = true
+			break
+		}
+	}
+	
+	// If cloud URIs detected, handle separately
+	if hasCloudURI {
+		return runVerifyCloudBackup(cmd, args)
+	}
+	
+	// Expand glob patterns for local files
 	var backupFiles []string
 	for _, pattern := range args {
 		matches, err := filepath.Glob(pattern)
@@ -139,3 +156,80 @@ func runVerifyBackup(cmd *cobra.Command, args []string) error {
 
 	return nil
 }
+
+// isCloudURI checks if a string is a cloud URI
+func isCloudURI(s string) bool {
+	return cloud.IsCloudURI(s)
+}
+
+// verifyCloudBackup downloads and verifies a backup from cloud storage
+func verifyCloudBackup(ctx context.Context, uri string, quick, verbose bool) (*restore.DownloadResult, error) {
+	// Download from cloud with checksum verification
+	result, err := restore.DownloadFromCloudURI(ctx, uri, restore.DownloadOptions{
+		VerifyChecksum: !quick, // Skip checksum if quick mode
+		KeepLocal:      false,
+	})
+	if err != nil {
+		return nil, err
+	}
+	
+	// If not quick mode, also run full verification
+	if !quick {
+		_, err := verification.Verify(result.LocalPath)
+		if err != nil {
+			result.Cleanup()
+			return nil, err
+		}
+	}
+	
+	return result, nil
+}
+
+// runVerifyCloudBackup verifies backups from cloud storage
+func runVerifyCloudBackup(cmd *cobra.Command, args []string) error {
+	fmt.Printf("Verifying cloud backup(s)...\n\n")
+	
+	successCount := 0
+	failureCount := 0
+	
+	for _, uri := range args {
+		if !isCloudURI(uri) {
+			fmt.Printf("⚠️  Skipping non-cloud URI: %s\n", uri)
+			continue
+		}
+		
+		fmt.Printf("☁️  %s\n", uri)
+		
+		// Download and verify
+		result, err := verifyCloudBackup(cmd.Context(), uri, quickVerify, verboseVerify)
+		if err != nil {
+			fmt.Printf("   ❌ FAILED: %v\n\n", err)
+			failureCount++
+			continue
+		}
+		
+		// Cleanup temp file
+		defer result.Cleanup()
+		
+		fmt.Printf("   ✅ VALID\n")
+		if verboseVerify && result.MetadataPath != "" {
+			meta, _ := metadata.Load(result.MetadataPath)
+			if meta != nil {
+				fmt.Printf("   Size: %s\n", metadata.FormatSize(meta.SizeBytes))
+				fmt.Printf("   SHA-256: %s\n", meta.SHA256)
+				fmt.Printf("   Database: %s (%s)\n", meta.Database, meta.DatabaseType)
+				fmt.Printf("   Created: %s\n", meta.Timestamp.Format(time.RFC3339))
+			}
+		}
+		fmt.Println()
+		successCount++
+	}
+	
+	fmt.Printf("\n✅ Summary: %d valid, %d failed\n", successCount, failureCount)
+	
+	if failureCount > 0 {
+		os.Exit(1)
+	}
+	
+	return nil
+}