…button

fidelio/server.R: use master's has_time check with DT::datatable for
non-time variables; fix list_of_variables_reactive() reference.

rice/ui.R: use master's simple uiOutput for gdxcompaR tab; remove
the HEAD-only Table tab (output$results_data_table).

rice/server.R: resolve three conflict blocks —
- gdxcompaRplot: master's DT/has_time structure + HEAD's index
  selector description labels + HEAD's second set (additional_set_id2)
  + tlen-aware year pre-computation + scale_x_continuous pretty breaks
- gdxcompaRstackedplot year filter: HEAD's second set handling +
  master's pathdir ordering + master's tlen-aware year column
- gdxcompaRstackedplot x-axis: aes(year,...) + pretty breaks

Also remove dead HEAD-only code: plot_data_rv, has_time_dim_rv,
hover_info, non_time_table, results_data_table, has_time_dim,
outputOptions.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Root-level scenarios were labeled with the cryptic "(root)" optgroup
header in the scenario selector. Now uses basename(results_dir) for a
meaningful folder name.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>