feat: add precise diagnostics and optional client copy logging controls

config/diagnostic.go

@@ -4,6 +4,8 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+
+	"git.yuntuo.hk/k2safe/go-omni/internal/configdiag"
 )
 
 // Error is a value-free diagnostic. Cause may contain private parser details;
@@ -56,6 +58,10 @@ func validationError(err error) *Error {
 		out.cause = err
 		return &out
 	}
+	var nested *configdiag.Error
+	if errors.As(err, &nested) {
+		return &Error{Field: nested.Field, Reason: nested.Reason, cause: err}
+	}
 	var c *ConfigError
 	if errors.As(err, &c) {
 		return &Error{Field: c.Field, Reason: c.Message, cause: err}