Make GH Pages dashboard include newly-added datasets automatically

[Copilot]

The GH Pages dashboard only rendered datasets hard-coded in DATASET_INFO, so datasets present in docs/data/all_catalogues.csv but missing from that table were silently omitted. This change makes CSV content the source of truth while preserving DATASET_INFO as an override layer.

• Dataset discovery now follows catalogue CSV

  • docs/index.html now builds dsNames from Object.keys(datasets) (parsed from all_catalogues.csv) instead of Object.keys(DATASET_INFO).
  • Any dataset in the CSV is eligible for rendering without manual JS edits.

• DATASET_INFO retained as optional overrides

  • docs/script.js documents DATASET_INFO as optional.
  • Added getDatasetInfo(name, rows):
    • returns override when present;
    • otherwise derives:
      • label: slug → titleized text (- / _ → spaces),
      • type: inferred from first row dataset_type,
      • period: computed from min/max year across earliest_date / latest_date.

• Validation path normalization for hemispheric variants

  • Replaced static folder map with datasetValidationDir(name) suffix normalization:
    • strips trailing _nh / _sh to resolve shared validation directories.

// Show any dataset available in the CSV. Use DATASET_INFO only as overrides.
const dsNames = Object.keys(datasets).filter(d => datasets[d] && datasets[d].length > 0);

// Use override if present; otherwise derive label/type/period from CSV rows.
const info = getDatasetInfo(name, datasets[name]);