feat(ui-primitives): outline-weight folder-open icon

The duotone folder_open_16 reads a rung heavier than the …Outline16 family
— its 20%-opacity inner fill looks filled beside pure-outline neighbors —
so an icon-button row mixing them looks mismatched. Same geometry, outline
layer only; the workspace surfaces keep the duotone original.

packages/client/ui-primitives/tests/icons.spec.tsx

@@ -16,8 +16,8 @@ const icons = Object.fromEntries(
 const iconNames = Object.keys(icons)
 
 describe('ic_ds_ icon set', () => {
-  it('exports the full P-I set (46 deepsuite + 17 figma extracts + three product glyphs outside those sets)', () => {
-    expect(iconNames.length).toBe(66)
+  it('exports the full P-I set (46 deepsuite + 18 figma extracts + three product glyphs outside those sets)', () => {
+    expect(iconNames.length).toBe(67)
   })
 
   it.each(iconNames)('%s renders an svg with currentColor fills and no hardcoded palette', (name) => {