Remove unused report output config

internal/config/validate.go

@@ -58,9 +58,6 @@ func Validate(cfg Config) error {
 	if cfg.Workspace.Root == "" {
 		return fmt.Errorf("workspace.root is required")
 	}
-	if cfg.Reports.OutputDir == "" {
-		return fmt.Errorf("reports.output_dir is required")
-	}
 	if len(cfg.Dayparts) == 0 {
 		return fmt.Errorf("dayparts must contain at least one entry")
 	}