Update .gitignore, add dist directory

dist/lib/schema/is-vector-field.js

@@ -0,0 +1,8 @@
+/**
+ * True when a field is a MariaDB native vector column.
+ */
+export default function isVectorField(field) {
+    if (!field)
+        return false;
+    return field.isVector === true || field.dataType === "VECTOR";
+}