fix: cache warmup using WebDriver for reliable authentication (#38449)

Co-authored-by: Superset Dev <dev@superset.apache.org>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/admin_docs/configuration/cache.mdx

@@ -86,6 +86,39 @@ instead requires a cachelib object.
 
 See [Async Queries via Celery](/admin-docs/configuration/async-queries-celery) for details.
 
+## Celery beat
+
+Superset has a Celery task that will periodically warm up the cache based on different strategies.
+To use it, add the following to your `superset_config.py`:
+
+```python
+from celery.schedules import crontab
+from superset.config import CeleryConfig
+
+# User that will be used to authenticate and render dashboards for cache warmup
+SUPERSET_CACHE_WARMUP_USER = "user_with_permission_to_dashboards"
+
+# Extend the default CeleryConfig to add cache warmup schedule
+class CustomCeleryConfig(CeleryConfig):
+    beat_schedule = {
+        **CeleryConfig.beat_schedule,
+        'cache-warmup-hourly': {
+            'task': 'cache-warmup',
+            'schedule': crontab(minute=0, hour='*'),  # hourly
+            'kwargs': {
+                'strategy_name': 'top_n_dashboards',
+                'top_n': 5,
+                'since': '7 days ago',
+            },
+        },
+    }
+
+CELERY_CONFIG = CustomCeleryConfig
+```
+
+This will cache the top 5 most popular dashboards every hour. For other
+strategies, check the `superset/tasks/cache.py` file.
+
 ## Caching Thumbnails
 
 This is an optional feature that can be turned on by activating its [feature flag](/admin-docs/configuration/configuring-superset#feature-flags) on config: