fix: Comprehensive Ctrl+C support across all I/O operations

- Add CopyWithContext to all long-running I/O operations
- Fix restore/extract.go: single DB extraction from cluster
- Fix wal/compression.go: WAL compression/decompression
- Fix restore/engine.go: SQL restore streaming
- Fix backup/engine.go: pg_dump/mysqldump streaming
- Fix cloud/s3.go, azure.go, gcs.go: cloud transfers
- Fix drill/engine.go: DR drill decompression
- All operations now check context every 1MB for responsive cancellation
- Partial files cleaned up on interruption

Version 4.2.4

main.go

@@ -16,7 +16,7 @@ import (
 
 // Build information (set by ldflags)
 var (
-	version   = "4.2.2"
+	version   = "4.2.4"
 	buildTime = "unknown"
 	gitCommit = "unknown"
 )