fix: normalize text input values

src/components/tickets/ticket-custom-fields.tsx

@@ -531,7 +531,15 @@ export function TicketCustomFieldsSection({ ticket }: TicketCustomFieldsSectionP
                     </FieldLabel>
                       <Input
                         id={fieldId}
-                      value={typeof value === "string" ? value : value ?? ""}
+                        value={
+                          typeof value === "string"
+                            ? value
+                            : typeof value === "number"
+                              ? String(value)
+                              : value != null
+                                ? String(value)
+                                : ""
+                        }
                         onChange={(event) => handleFieldChange(field, event.target.value)}
                       />
                     {helpText}