feat(whatsapp): QWEN primary AI backend, Hermes fallback, conversation history, vehicle persistence, demo prompts

- Add QWEN (qwen3.6) as primary AI backend with short system prompt
- Hermes remains as fallback with 45s timeout
- Increase QWEN timeout to 35s, max_tokens to 4000
- Add conversation history loading from whatsapp_messages (last 4 msgs)
- Persist detected vehicle in whatsapp_sessions table
- Add 'limpiar chat' / 'nuevo chat' / 'reset' commands to clear history
- Fix CSS conflict: rename whatsapp chat-panel classes to wa-chat-panel
- Fix JS ID conflicts with chat.js widget (waChatPanel, waChatMessages, etc.)
- Improve no-stock response: conversational with alternatives
- Split search_query by | for multi-part lookups
- Add DEMO_PROMPTS.md and DEMO_PROMPTS_V2.md

tests/e2e/inventory.spec.js

@@ -1,21 +1,88 @@
 const { test, expect } = require('@playwright/test');
 
-test.describe('Nexus POS — Inventory', () => {
-  test('inventory page loads with table or grid', async ({ page }) => {
-    await page.goto('/pos/inventory');
-    await expect(page.locator('#inventoryTable, .data-table, #partsGrid, .grid, table')).toBeVisible({ timeout: 10000 });
-    const content = await page.locator('body').textContent();
-    expect(content).toMatch(/inventario|stock|producto|parte/i);
+const FAKE_TOKEN = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjk5OTk5OTk5OTksIm5hbWUiOiJUZXN0IFVzZXIifQ.signature';
+
+async function setupAuth(page) {
+  await page.goto('/pos/login');
+  await page.evaluate((token) => {
+    localStorage.setItem('pos_token', token);
+    localStorage.setItem('pos_tenant_id', '11');
+  }, FAKE_TOKEN);
+}
+
+async function mockInventoryAPIs(page) {
+  await page.route(/\/pos\/api\/inventory\/items\?page=.*&per_page=.*/, async (route) => {
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({
+        data: [
+          {
+            id: 1,
+            barcode: '123456789',
+            part_number: 'TEST-001',
+            name: 'Producto de prueba',
+            brand: 'TestBrand',
+            stock: 10,
+            cost: 50.0,
+            price_1: 100.0,
+            price_2: 90.0,
+            price_3: 80.0,
+            location: 'A-1',
+          },
+        ],
+        pagination: { page: 1, total_pages: 1, total: 1 },
+      }),
+    });
   });
 
-  test('product detail modal or panel opens', async ({ page }) => {
+  await page.route(/\/pos\/api\/inventory\/items\/\d+/, async (route) => {
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({
+        id: 1,
+        barcode: '123456789',
+        part_number: 'TEST-001',
+        name: 'Producto de prueba',
+        brand: 'TestBrand',
+        location: 'A-1',
+        stock: 10,
+        cost: 50.0,
+        price_1: 100.0,
+        price_2: 90.0,
+        price_3: 80.0,
+        history: [],
+      }),
+    });
+  });
+}
+
+test.describe('Nexus POS — Inventory', () => {
+  test('inventory page loads with table', async ({ page }) => {
+    await setupAuth(page);
+    await mockInventoryAPIs(page);
     await page.goto('/pos/inventory');
-    // Try clicking first row or card
-    const firstRow = page.locator('.data-table tbody tr, .grid .card, .inventory-row').first();
-    await firstRow.waitFor({ state: 'visible', timeout: 10000 }).catch(() => {});
-    if (await firstRow.isVisible().catch(() => false)) {
-      await firstRow.click();
-      await expect(page.locator('.modal, .detail-panel, #detailPanel, [role="dialog"]')).toBeVisible({ timeout: 5000 });
-    }
+
+    await expect(page).toHaveTitle(/Inventario/i);
+    await expect(page.locator('#stockTable')).toBeVisible({ timeout: 5000 });
+    // Wait for virtual-scroll rows to render
+    await page.waitForSelector('#productTableBody tr', { timeout: 5000 });
+    const rows = page.locator('#productTableBody tr');
+    await expect(rows.first()).toBeVisible();
+  });
+
+  test('product detail modal opens', async ({ page }) => {
+    await setupAuth(page);
+    await mockInventoryAPIs(page);
+    await page.goto('/pos/inventory');
+
+    await page.waitForSelector('#productTableBody tr', { timeout: 5000 });
+    const firstRow = page.locator('#productTableBody tr').first();
+    await firstRow.click();
+
+    // The detail view opens inside #historyModal
+    await expect(page.locator('#historyModal')).toHaveClass(/is-open/, { timeout: 5000 });
+    await expect(page.locator('#historyContent')).toContainText('Producto de prueba');
   });
 });