feat(main): add silent mode to suppress output messages

* implement --silent flag to control output verbosity
* update error handling to restore stderr after silent mode
* enhance progress reporting in PostgreSQL reader

cmd/relspec/prisma_options.go

@@ -1,6 +1,9 @@
 package main
 
 import (
+	"fmt"
+	"os"
+
 	"git.warky.dev/wdevs/relspecgo/pkg/readers"
 	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 )
@@ -11,6 +14,9 @@ func newReaderOptions(filePath, connString string) *readers.ReaderOptions {
 		ConnectionString: connString,
 		Prisma7:          prisma7,
 		StrictDirectives: strictDirectives,
+		Progress: func(message string) {
+			fmt.Fprintf(os.Stderr, "      → %s\n", message)
+		},
 	}
 }