feat(@fn_library): extract 2 components + improve 2 from Claude Design export

From: sources/frontend_designs/Ads Analytics Dashboard _standalone_.html

New components:
- funnel_chart_ts_ui — visualización de funnel de conversión con barras
  degradadas y tasa entre etapas como Badge semántico.
- heatmap_grid_ts_ui — matriz rows × cols con intensidad color-mix sobre
  el primary color. Genérica (day×hour, cohort, correlation...).

Improvements:
- alert_ts_ui v1.1.0 — añadidas variantes semánticas success, warning, info
  (antes: solo default y destructive).
- data_table_ts_ui v1.1.0 — prop opcional density: compact | cozy | roomy.
  No rompe API existente (default 'cozy' = comportamiento previo).

Barrel frontend/functions/ui/index.ts actualizado con los dos nuevos
exports y el type DataTableDensity.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/functions/ui/index.ts

@@ -36,7 +36,11 @@ export type { Series } from './chart_container'
 
 // Data
 export { DataTable } from './data_table'
-export type { DataTableProps, ColumnDef } from './data_table'
+export type { DataTableProps, ColumnDef, DataTableDensity } from './data_table'
+export { FunnelChart } from './funnel_chart'
+export type { FunnelChartProps, FunnelStage } from './funnel_chart'
+export { HeatmapGrid } from './heatmap_grid'
+export type { HeatmapGridProps, HeatmapColumn } from './heatmap_grid'
 
 // Mantine Provider
 export { FnMantineProvider } from './mantine_provider'