add duckdb-ui-client & other ts pkgs (#10)

* add duckdb-ui-client & other ts pkgs

* workflow fixes

* fix working dir

* no sparse checkout; specify package.json path

* path to pnpm-lock.yaml

* add check & build test

* workflow step descriptions

* use comments & names

* one more naming tweak

ts/pkgs/duckdb-ui-client/test/util/functions/randomString.test.ts

@@ -0,0 +1,14 @@
+import { expect, suite, test } from 'vitest';
+import { randomString } from '../../../src/util/functions/randomString';
+
+suite('randomString', () => {
+  test('default length', () => {
+    expect(randomString().length).toBe(12);
+  });
+  test('custom length', () => {
+    expect(randomString(5).length).toBe(5);
+  });
+  test('custom chars', () => {
+    expect(randomString(3, 'xy')).toMatch(/[xy][xy][xy]/);
+  });
+});