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/root.go

@@ -14,6 +14,7 @@ var (
 	buildDate        = "unknown"
 	prisma7          bool
 	noVersion        bool
+	silent           bool
 	strictDirectives bool
 )
 
@@ -73,6 +74,7 @@ func init() {
 	rootCmd.AddCommand(reportCmd)
 	rootCmd.PersistentFlags().BoolVar(&prisma7, "prisma7", false, "Use Prisma 7 generator conventions when reading/writing Prisma schemas")
 	rootCmd.PersistentFlags().BoolVar(&noVersion, "no-version", false, "Suppress the RelSpec version header")
+	rootCmd.PersistentFlags().BoolVar(&silent, "silent", false, "Suppress progress and status messages (errors are still shown)")
 	rootCmd.PersistentFlags().BoolVar(&strictDirectives, "strict-directives", false, "Fail on unknown or untranslatable DBML dialect directives (@postgres:, @sqlite:, …)")
 }