Review fixes

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/validator/validator_prosemirror.go

@@ -25,7 +25,11 @@ import (
 // strings are allowed.
 func ProseMirrorDocumentContent() ValidatorFunc {
 	return func(value any) *ValidationError {
-		s, ok := value.(string)
+		actualValue, isNil := dereferenceValue(value)
+		if isNil {
+			return nil
+		}
+		s, ok := actualValue.(string)
 		if !ok {
 			return newValidationError(ErrorCodeInvalidFormat, "value must be a string")
 		}

pkg/validator/validator_prosemirror_test.go

@@ -31,6 +31,8 @@ func TestProseMirrorDocumentContent(t *testing.T) {
 		{"valid doc", validDoc, false},
 		{"plain text", "not json", true},
 		{"non-doc root", `{"type":"paragraph","content":[]}`, true},
+		{"nil value", nil, false},
+		{"nil *string", (*string)(nil), false},
 		{"non-string", 1, true},
 	}