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/alert.tsx

@@ -1,11 +1,14 @@
 import * as React from 'react'
 import { Alert as MantineAlert, Box, Text } from '@mantine/core'
 
-type AlertVariant = 'default' | 'destructive'
+type AlertVariant = 'default' | 'destructive' | 'success' | 'warning' | 'info'
 
 const variantColorMap: Record<AlertVariant, string | undefined> = {
   default: undefined,
   destructive: 'red',
+  success: 'green',
+  warning: 'yellow',
+  info: 'blue',
 }
 
 function Alert({