@spec group_cells([PgFlow.RunHistoryCell.t()]) :: %{
  optional(String.t() | nil) => [PgFlow.RunHistoryCell.t()]
}

Groups run-history cells by step slug for grid rendering.

Renders a run history grid.

Attributes

• :grid_data - Map of step_slug => list of run results
• :steps - Ordered list of step slugs for rows
• :max_runs - Maximum number of runs to display
• :base_path - Base path for navigation links

Attributes

• grid_data (:map) (required)
• steps (:list) (required)
• max_runs (:integer) - Defaults to 50.
• base_path (:string) - Defaults to "/pgflow".