test(tables): pin the folder scope to single-select

`workspace-folder-selector` stores a string when multiSelect is falsy and
an array when it is true. TableSelector's narrowing reads a string, so
flipping this field to multi-select would make the scope read as absent
and the picker would silently stop filtering. The coupling was real but
unpinned; the File block's equivalent is deliberately multi-select.

Author: mzxchandra

apps/sim/blocks/blocks/table-folders.test.ts

@@ -206,6 +206,18 @@ describe('table_v2 folder scope narrows the table picker', () => {
     expect(TableV2Block.inputs).not.toHaveProperty('folderSelection')
   })
 
+  it('stays single-select, because the picker reads its value as a path string', () => {
+    /*
+     * `workspace-folder-selector` stores a STRING when multiSelect is falsy and
+     * an ARRAY when it is true. TableSelector's narrowing reads the value as a
+     * string, so turning this multi-select would make the scope read as absent
+     * and the picker would silently stop filtering — failing open, which is the
+     * safe direction but not the intended one. The File block's equivalent IS
+     * multi-select; tables narrow to one folder.
+     */
+    expect(subBlock('folderSelection')?.multiSelect).toBeFalsy()
+  })
+
   it('has no advanced-mode twin, because a resolved reference would be discarded', () => {
     expect(subBlock('folderSelection')?.mode).toBe('basic')
     expect(subBlock('folderSelection')?.canonicalParamId).toBeUndefined()