Get the static task list for a Databricks job

Return every task defined on the job's workflow DAG (regardless of whether the task has been run or has an Auto Tune recommendation). Sourced from dbx_job_tasks_inventory.

The Auto Tune drawer DAG and the overview "Tasks" tile use this as the authoritative task list so they don't depend on the recs feed or task-runs windowing for the denominator.

workspace_id only scopes the estimated_cost_per_hr lookup (:func:get_task_estimated_cost_per_hr_map) — the ClickHouse depends_on_map / cluster_map reads are pre-existing scope and remain (job_id, instance_id)-only, so a cross-workspace job_id collision could still surface the wrong cluster spec.