feat(app/e2e): introduce withWorkspace fixture and DSL helpers (#717)

Adds a `withWorkspace` Playwright fixture plus composable helpers
(permissions, sidebar, composer, agent-stream, settings) so specs read
as user-level intent. Migrates workspace-lifecycle and settings-host-page
to the new DSL as proof.

packages/app/e2e/helpers/permissions.ts

@@ -0,0 +1,17 @@
+import { expect, type Page } from "@playwright/test";
+
+export async function waitForPermissionPrompt(page: Page, timeout = 30_000): Promise<void> {
+  await expect(page.getByTestId("permission-request-question").first()).toBeVisible({ timeout });
+}
+
+export async function allowPermission(page: Page): Promise<void> {
+  const acceptButton = page.getByTestId("permission-request-accept").first();
+  await expect(acceptButton).toBeVisible({ timeout: 5_000 });
+  await acceptButton.click();
+}
+
+export async function denyPermission(page: Page): Promise<void> {
+  const denyButton = page.getByTestId("permission-request-deny").first();
+  await expect(denyButton).toBeVisible({ timeout: 5_000 });
+  await denyButton.click();
+}