fix(app/e2e): fix composer-lock test — mock provider + prompt so lock releases (#739)

* fix(app/e2e): fix composer-lock test — use mock provider + prompt so lock releases

Two bugs in the "composer is locked while new workspace agent is being
created" test:

1. expectComposerDisabled used toBeDisabled() but React Native TextInput
   with editable={false} renders as <textarea readonly> on web, not
   <textarea disabled>. Fixed to not.toBeEditable().

2. clickNewWorkspaceButton created an agent with no prompt, leaving the
   agent permanently "idle". showPendingCreateSubmitLoading only clears
   when authoritativeStatus is non-bootstrapping, but "idle" counts as
   bootstrapping — so the composer lock never released. Fixed by opening
   the new-workspace composer, filling a prompt, then clicking Create so
   the mock agent transitions to "running" after agent_created is released.

Also switches buildCreateAgentPreferences to provider "mock" with the
ten-second-stream model so E2E tests exercise app behavior without
depending on real provider availability.

* fix(app): add aria-checked to Switch for E2E toBeChecked() assertions

React Native Web does not map accessibilityState.checked to aria-checked
for role="switch", so Playwright's toBeChecked() always finds the element
unchecked. Adding aria-checked={value} directly to the Pressable sets the
attribute explicitly.

Update the switch.test.tsx mock to accept and pass through the explicit
aria-checked prop, keeping the mock faithful to the fixed component.

packages/app/src/components/ui/switch.tsx

@@ -100,6 +100,7 @@ export function Switch({
       accessibilityRole="switch"
       accessibilityState={accessibilityState}
       accessibilityLabel={accessibilityLabel}
+      aria-checked={value}
       testID={testID}
       style={pressableStyle}
     >