test(e2e): add admin smoke test covering the tinacms upgrade regressions

Three Playwright assertions against the TinaCMS admin at /admin/index.html.
Each one catches a specific failure mode we hit during the 3.4 -> 3.8
upgrade so a future regression is caught up front:

1. "loads without the 'Failed loading assets' placeholder" -- catches the
   IPv4/IPv6 binding mismatch. If tina-ipv4-proxy.js dies or the
   Dockerfile entrypoint loses its spawn line, the admin/index.html's
   hardcoded http://localhost:4001/... script tags can't resolve and
   Tina renders its built-in error placeholder. The assertion sees that.

2. "every collection in tina/config.ts is reachable by URL" -- walks each
   #/collections/<name> hash route and asserts its page header renders.
   Catches schema regressions (collection removed, renamed, broken).
   Uses location.hash mutation rather than page.goto so Tina's React app
   doesn't full-reload and re-render the edit-mode modal mid-test.

3. "clicking a row title opens the form-only admin editor, not visual
   edit" -- asserts that the title click on a News row routes to
   /collections/edit/news/... rather than the broken visual-edit iframe.
   Re-adding `ui.router` to any collection would break this.

Headless playwright contexts have no Tina session cookie so they see the
one-time "Enter Edit Mode" modal that real users only see once. The
shared dismissEditModeModal helper waits for it (networkidle fires
before the modal renders) and clicks it.

Author: adamjohnwright

e2e/admin.spec.ts

@@ -0,0 +1,106 @@
+import { test, expect, Page } from '@playwright/test';
+
+// Smoke test for the TinaCMS admin shell at /admin/index.html.
+//
+// Catches the two regressions we hit during the 3.4 -> 3.8 upgrade:
+//
+//   1. @tinacms/cli@2.1.8+ init hang -- if `tinacms dev` never reaches
+//      its "Dev Server is active" state, `ng serve` is never spawned and
+//      the page never loads at all (connection refused on :4200).
+//
+//   2. `tinacms dev` binds only to ::1:4001 -- the admin's hardcoded
+//      `http://localhost:4001/...` script tags can't resolve via the
+//      IPv4-only docker port-publish. Tina then renders its built-in
+//      "Failed loading TinaCMS assets" placeholder. The IPv4 forwarder
+//      at projects/website-angular/src/scripts/tina-ipv4-proxy.js must
+//      be running for the assets to load.
+//
+// Note on the "Enter Edit Mode" modal: a fresh playwright context has
+// no Tina session cookie, so Tina shows a one-time modal before exposing
+// the sidebar/collections. A real human only sees this once.
+async function dismissEditModeModal(page: Page) {
+  // Wait for the modal to actually render (networkidle fires before Tina's
+  // React app mounts it). Short timeout because if no modal appears, we
+  // were already past it.
+  const enterEdit = page.getByRole('button', { name: /enter edit mode/i });
+  try {
+    await enterEdit.waitFor({ state: 'visible', timeout: 5000 });
+    await enterEdit.click();
+    await page.waitForTimeout(1500);
+  } catch {
+    // No modal -- already in edit mode.
+  }
+}
+
+async function enterAdmin(page: Page) {
+  await page.goto('/admin/index.html', { waitUntil: 'networkidle' });
+  await dismissEditModeModal(page);
+}
+
+test.describe('TinaCMS admin shell', () => {
+  test('loads without the "Failed loading assets" placeholder', async ({ page }) => {
+    await page.goto('/admin/index.html', { waitUntil: 'networkidle' });
+    await expect(page).toHaveTitle(/TinaCMS/i);
+    await expect(page.locator('#no-assets-placeholder')).toHaveCount(0);
+    await expect(page.locator('text=Failed loading TinaCMS assets')).toHaveCount(0);
+  });
+
+  test('every collection in tina/config.ts is reachable by URL', async ({ page }) => {
+    // Driving Tina's collapsible sidebar via the hamburger is fragile (the
+    // hamburger is layered behind the llama logo SVG which intercepts
+    // pointer events). Hitting each collection's hash URL exercises the
+    // same code path -- if Tina rejects the URL the page header label
+    // doesn't render. This catches schema regressions (collection
+    // removed, renamed, or broken by a config change).
+    await page.setViewportSize({ width: 1440, height: 900 });
+    await enterAdmin(page);
+
+    for (const { name, label } of [
+      { name: 'about', label: 'About' },
+      { name: 'news', label: 'News' },
+      { name: 'content', label: 'Content' },
+      { name: 'reactome_research_spotlights', label: 'Reactome Research Spotlights' },
+      { name: 'documentation', label: 'Documentation' },
+      { name: 'community', label: 'Community' },
+    ]) {
+      await page.evaluate((n) => {
+        window.location.hash = `#/collections/${n}`;
+      }, name);
+      await page.waitForTimeout(1500);
+      await expect(page.getByRole('heading', { name: label, exact: true })).toBeVisible({
+        timeout: 10000,
+      });
+    }
+  });
+
+  test('clicking a row title opens the form-only admin editor, not visual edit', async ({
+    page,
+  }) => {
+    // Tina's collection table needs horizontal room. The default 1280x720
+    // viewport renders the table in a layout where rows don't materialize
+    // until enough columns fit.
+    await page.setViewportSize({ width: 1440, height: 900 });
+    await enterAdmin(page);
+
+    // News is the worst case for visual editing: long filenames hide the
+    // kebab "Edit in Admin" action off-screen. With `ui.router` removed
+    // (commit 4f2c9c8 prior), the title click instead routes to the
+    // form-only admin editor. Re-adding ui.router would re-introduce the
+    // visual-edit iframe trap and this assertion would fail.
+    // Don't `page.goto` to a new URL -- it triggers a full reload that
+    // re-renders the edit-mode modal even after we dismissed it in
+    // enterAdmin. Mutating location.hash keeps Tina's React app mounted
+    // and just routes within it.
+    await page.evaluate(() => {
+      window.location.hash = '#/collections/news';
+    });
+    await page.waitForTimeout(2500);
+    const firstRowLink = page.locator('tbody tr a').first();
+    await expect(firstRowLink).toBeVisible({ timeout: 15000 });
+    await firstRowLink.click();
+
+    await expect(page).toHaveURL(/\/admin\/index\.html#\/collections\/edit\/news\//, {
+      timeout: 10000,
+    });
+  });
+});