refactor: two-screen app-list editor with native List layout

Screen 1 is a plain List (name field, the apps the list contains via
FamilyControls token Labels, and an Edit Apps button); screen 2 pushes
Apple's FamilyActivityPicker whose Save applies the selection back.
Documents that the picker silently drops selections without real
FamilyControls authorization (mocked in -ui-testing launches).

Co-Authored-By: Claude <noreply@anthropic.com>

AGENTS.md

@@ -126,5 +126,12 @@ Gotchas learned the hard way:
 - Time Limit / Open Limit rules are fully modeled, editable, and displayed,
   but not enforced (see above).
 - `FamilyActivityPicker` shows few apps on the simulator; fine on device.
+- `FamilyActivityPicker` **silently ignores selections** (binding never
+  updates, rows still show checkmarks) unless real FamilyControls
+  authorization has been granted — in `-ui-testing` launches authorization
+  is mocked, so picker selections can never be asserted in UI tests. To
+  verify selection flows manually on the simulator, launch without
+  `-ui-testing`, complete onboarding, and approve the system Screen Time
+  prompts ("Allow with Passcode" works on the simulator).
 - Distribution (App Store) requires Apple's approval for the Family Controls
   entitlement; development builds work with the dev entitlement.