Add a tile to a dashboard.

A tile renders exactly one saved query: query_id names it, chart_type is one of line, area, bar, stacked_bar, pie, kpi or table, and pos_x / pos_y / pos_w / pos_h place it on the grid (origin top-left, width and height in grid cells). chart_config and param_bindings are opaque JSON objects the dashboard UI owns; both default to {}.

The saved query must be one of your organization’s — a query_id from anywhere else reads as “does not exist”.