Clear the stats cache.

Query Parameters:

• pattern: Optional pattern to match cache keys (e.g., 'summary', 'trends')

Allowed patterns: summary, trends, geographic, tasks, executions, users, activity

Example Response (success): { "data": { "success": true, "message": "Cache cleared successfully" } }

Example Response (with pattern): { "data": { "success": true, "message": "Cache cleared successfully for pattern: summary" } }

Returns: JSON response indicating success or failure of cache clearing operation