get charts

Find and return renderable Economic-Survey CHART FIGURES. `query` full-text-searches each chart's label + caption + description (its legend/axis/source text + chapter) — e.g. 'fiscal deficit trends', 'GST collections', 'inflation' — to resolve the right figure; `chart` filters by label ('Chart II.1'), `fiscal_year` by Survey edition ('2025-26'). Each result includes an `image_url` (a PNG rendered