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-data-values/test/DuckDBTimeValue.test.ts

@@ -0,0 +1,18 @@
+import { expect, suite, test } from 'vitest';
+import { DuckDBTimeValue } from '../src/DuckDBTimeValue';
+
+suite('DuckDBTimeValue', () => {
+  test('should render a normal time value to the correct string', () => {
+    expect(new DuckDBTimeValue(45296000000n).toString()).toStrictEqual(
+      '12:34:56',
+    );
+  });
+  test('should render the max time value to the correct string', () => {
+    expect(new DuckDBTimeValue(86399999999n).toString()).toStrictEqual(
+      '23:59:59.999999',
+    );
+  });
+  test('should render the min time value to the correct string', () => {
+    expect(new DuckDBTimeValue(0n).toString()).toStrictEqual('00:00:00');
+  });
+});