ci(web): Phase P6 — vite build in PR CI + headless E2E gate on trunk publishes (#1445)

- ci.yml: build step (vite build via turbo) runs on every PR pipeline after test
- publish.yml: e2e step boots the gateway from built dist (HOME/cwd-isolated
  throwaway PGlite) and runs the Playwright suite headless inside
  mcr.microsoft.com/playwright:v1.58.2-noble against the SPA bundle served
  exactly as production serves it; both kaniko publishes now gate on e2e
- serve-spa.ts: strip query strings before asset resolution; immutable
  cache-control for hashed assets (onSend hook); e2e spec covers both
- e2e suite hardened: globalSetup seeds admin+member through real
  bootstrap/better-auth APIs (Origin header for CSRF), loginAs waits for the
  post-login redirect (fixes 27-skipped race), stale #152-era assertions
  rewritten to the current command-driven UI, strict-mode violations fixed
  with level-1 heading queries and .or() auto-retrying locators
- verify-release mirrors the new build stage; playwright artifacts ignored

apps/web/e2e/chat.spec.ts

@@ -9,37 +9,27 @@ test.describe('Chat page', () => {
     test.skip(!url.includes('/chat'), 'No seeded test user — skipping authenticated tests');
   });
 
-  test('chat page loads and shows the welcome message or conversation list', async ({ page }) => {
+  test('chat page loads and shows the conversation area', async ({ page }) => {
     await page.goto('/chat');
-    // Either there are conversations listed or the welcome empty-state is shown
-    const hasWelcome = await page
-      .getByRole('heading', { name: /welcome to mosaic chat/i })
-      .isVisible()
-      .catch(() => false);
-    const hasConversationPanel = await page
-      .locator('[data-testid="conversation-list"], nav, aside')
-      .first()
-      .isVisible()
-      .catch(() => false);
-
-    expect(hasWelcome || hasConversationPanel).toBe(true);
+    await expect(page.getByRole('heading', { level: 1, name: /chat/i })).toBeVisible({
+      timeout: 10_000,
+    });
+    await expect(page.getByRole('log', { name: /conversation/i })).toBeVisible();
   });
 
-  test('new conversation button is visible', async ({ page }) => {
+  test('message composer input is visible', async ({ page }) => {
     await page.goto('/chat');
-    // "Start new conversation" button or a "+" button in the sidebar
-    const newConvButton = page.getByRole('button', { name: /new conversation|start new/i }).first();
-    await expect(newConvButton).toBeVisible({ timeout: 10_000 });
+    await expect(page.getByLabel('Message')).toBeVisible({ timeout: 10_000 });
   });
 
-  test('clicking new conversation shows a chat input area', async ({ page }) => {
+  test('command panel lists /new and exposes the run controls', async ({ page }) => {
     await page.goto('/chat');
-    // Find any button that creates a new conversation
-    const newBtn = page.getByRole('button', { name: /new conversation|start new/i }).first();
-    await newBtn.click();
-    // After creating, a text input for sending messages should appear
-    const chatInput = page.getByRole('textbox').or(page.locator('textarea')).first();
-    await expect(chatInput).toBeVisible({ timeout: 10_000 });
+    // Conversations are command-driven: /new starts one via the commands panel.
+    const commandList = page.getByRole('list', { name: /available commands/i });
+    await expect(commandList).toBeVisible({ timeout: 10_000 });
+    await expect(commandList.getByText('/new', { exact: true })).toBeVisible();
+    await expect(page.getByLabel('Command name')).toBeVisible();
+    await expect(page.getByRole('button', { name: /run command/i })).toBeVisible();
   });
 
   test('sidebar navigation is present on chat page', async ({ page }) => {