Fix kbRoot browse ignoring Typert Result from directoryPicker.pick.

Unwrap { ok, value } so the chosen folder path lands in the field and auto-saves.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/kb-pick-result.test.mjs

@@ -0,0 +1,48 @@
+/**
+ * Directory-picker Result unwrapping (mirrors controller helper).
+ */
+
+import assert from 'node:assert/strict'
+import test from 'node:test'
+
+function unwrapDirectoryPickResult(result) {
+  if (result === null) return null
+  if (typeof result === 'string') {
+    const trimmed = result.trim()
+    return trimmed === '' ? null : trimmed
+  }
+  if (typeof result !== 'object' || Array.isArray(result)) return undefined
+  const row = result
+  if (row.ok === false) {
+    throw new Error(row.error?.message || 'directoryPicker/pick failed')
+  }
+  if ('value' in row) {
+    if (row.value === null) return null
+    if (typeof row.value === 'string') {
+      const trimmed = row.value.trim()
+      return trimmed === '' ? null : trimmed
+    }
+    return undefined
+  }
+  return undefined
+}
+
+test('unwrap bare string path', () => {
+  assert.equal(unwrapDirectoryPickResult('D:\\kb'), 'D:\\kb')
+})
+
+test('unwrap typert Result value', () => {
+  assert.equal(unwrapDirectoryPickResult({ ok: true, value: 'D:\\kb\\ioh' }), 'D:\\kb\\ioh')
+})
+
+test('unwrap cancel null', () => {
+  assert.equal(unwrapDirectoryPickResult(null), null)
+  assert.equal(unwrapDirectoryPickResult({ ok: true, value: null }), null)
+})
+
+test('reject Result error', () => {
+  assert.throws(
+    () => unwrapDirectoryPickResult({ ok: false, error: { message: 'no native' } }),
+    /no native/,
+  )
+})