fix: correct membership back flow and add onboarding paywall

frontend/tests/membership-page.test.ts

@@ -5,6 +5,8 @@ import test from "node:test";
 const projectFile = (path: string) => new URL(`../${path}`, import.meta.url);
 const readProjectFile = (path: string) => readFileSync(projectFile(path), "utf8");
 const globalStyles = readProjectFile("src/app/globals.css");
+const homePageSource = readProjectFile("src/app/page.tsx");
+const onboardingPaywallSource = readProjectFile("src/components/onboarding-redeem-paywall.tsx");
 const pageSource = readProjectFile("src/app/membership/page.tsx");
 const ordersPageSource = readProjectFile("src/app/membership/orders/page.tsx");
 const tabsSource = readProjectFile("src/components/ui/tabs.tsx");
@@ -216,6 +218,22 @@ test("independent orders page preserves loading, empty, error, refresh and list
   assert.match(membershipLib, /paid: "已支付"/);
 });
 
+test("orders return replaces its history entry so membership back cannot reopen orders", () => {
+  assert.match(ordersPageSource, /<Link className="membership-back" href="\/membership" replace/);
+});
+
+test("finished starter questions open the redeem paywall only for accounts without access", () => {
+  assert.match(homePageSource, /!starterHomeVisible/);
+  assert.match(homePageSource, /account\.credits > 0/);
+  assert.match(homePageSource, /account\.activeSubscription\?\.status === "active"/);
+  assert.match(homePageSource, /setOnboardingPaywallOpen\(true\)/);
+  assert.match(homePageSource, /<OnboardingRedeemPaywall/);
+  assert.match(onboardingPaywallSource, /入门问题已经准备好/);
+  assert.match(onboardingPaywallSource, /fetch\("\/api\/redeem"/);
+  assert.match(onboardingPaywallSource, /兑换并继续/);
+  assert.match(onboardingPaywallSource, /membershipHref\("onboarding-paywall"\)/);
+});
+
 test("payment and plan copy points users to the separate orders page", () => {
   assert.match(pageSource, /本页会自动检查支付状态并刷新余额。/);
   assert.match(pageSource, /「订单记录」页面/);

frontend/tests/sidebar-contract.test.ts

@@ -173,9 +173,10 @@ test("removes the user-facing admin entry and routes credit control to membershi
 test("composes the chat page with the app sidebar shell", () => {
   const page = readProjectFile("src/app/page.tsx");
 
-  assert.match(page, /<SidebarProvider escapeBlocked=\{accountMenuOpen \|\| activeAccountDialog !== null\}>/);
+  assert.match(page, /const modalOpen = activeAccountDialog !== null \|\| onboardingPaywallOpen/);
+  assert.match(page, /<SidebarProvider escapeBlocked=\{accountMenuOpen \|\| modalOpen\}>/);
   assert.match(page, /<main className="chat-app">[\s\S]*<AppSidebar\b/);
-  assert.match(page, /<SidebarInset className="chat-panel" inert=\{activeAccountDialog !== null\}>/);
+  assert.match(page, /<SidebarInset className="chat-panel" inert=\{modalOpen\}>/);
   assert.match(page, /<SidebarTrigger placement="inset" \/>/);
 });
 
@@ -192,7 +193,7 @@ test("blocks the provider mobile Escape action behind layered account UI", () =>
   const page = readProjectFile("src/app/page.tsx");
   const sidebar = readProjectFile("src/components/ui/sidebar.tsx");
 
-  assert.match(page, /escapeBlocked=\{accountMenuOpen \|\| activeAccountDialog !== null\}/);
+  assert.match(page, /escapeBlocked=\{accountMenuOpen \|\| modalOpen\}/);
   assert.match(sidebar, /event\.key === "Escape" && isMobile && openMobile && !escapeBlocked/);
 });