Provide shortcut for TQL Eval


In some cases we use `TQL Eval` for promql query, it requires the time window tuple (start, end, step). Would be helpful if we have an widget to generate this tuple, for example "Last 5 minutes", "Last 1 hour". We can reuse the widget from our promql UI.

Start at the TQL Eval entry point and inspect the existing widget in the PromQL UI, which the issue identifies for reuse. Determine how the start, end, and step tuple is represented, then verify that shortcuts such as “Last 5 minutes” and “Last 1 hour” produce the expected values.

Written by the indexing model from the issue text.