refactor: migrar tests E2E a persistent context

global-setup.ts:
- Usa launchPersistentContext en vez de browser.newContext()
- Reemplaza storageState por marker file para cache de sesion
- Captura logs de consola del browser para debug
- Screenshots y HTML dump en caso de error

playwright.config.ts:
- Elimina storageState (ahora via persistent context fixture)
- Screenshots siempre activas, video y trace en failures

Tests (login, assistant-bot, asistente-2):
- Importan test/expect desde persistent-context fixture
- Usan handleElementDialogs() en vez de espera manual de rooms
- Nuevo test de threads en asistente-2: verifica que el bot
  responde dentro del thread cuando se le habla por thread

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

e2e/playwright.config.ts

@@ -19,12 +19,15 @@ export default defineConfig({
   use: {
     baseURL: process.env.ELEMENT_URL || "http://localhost:8080",
     headless: true,
-    screenshot: "only-on-failure",
-    trace: "on-first-retry",
+    screenshot: "on",
+    trace: "retain-on-failure",
+    video: "retain-on-failure",
     actionTimeout: 30_000,
-    storageState: path.resolve(__dirname, ".auth/state.json"),
+    // NO usamos storageState — usamos persistent context para preservar IndexedDB
   },
 
+  outputDir: "./test-results",
+
   globalSetup: "./global-setup.ts",
 
   projects: [