List tasks with filtering, sorting, and pagination
project_id (UUID)conversation_id (UUID)user_id (string)status (active | completed | failed | timeout)loop_detected (boolean)has_failures (boolean)has_issues (boolean; loops OR failures)start_date, end_date (ISO datetime)page (default 1)page_size (default 20, max 100)sort_by (started_at | completed_at | total_traces | total_tool_calls | total_tokens | total_cost_usd | total_latency_ms | status)sort_order (asc | desc)