refactor: migrate frontend from shadcn/Tailwind to Mantine v9

Reescribe todos los componentes UI para usar Mantine v9 en lugar de shadcn/Tailwind.
Elimina cn(), CVA, components.json, theme_provider custom y globals.css con Tailwind.
Añade 25+ componentes nuevos (AppShell, AuthForm, DatePickerInput, Dropzone, etc.)
y MantineProvider como wrapper estándar del sistema de temas.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/functions/ui/radio_group.tsx

@@ -1,61 +1,56 @@
 import * as React from "react"
-import { RadioGroup as RadioGroupPrimitive } from "@base-ui/react/radio-group"
-import { Radio } from "@base-ui/react/radio"
-import { cn } from "../core/cn"
+import { Radio } from "@mantine/core"
 
-function RadioGroup({ className, ...props }: RadioGroupPrimitive.Props) {
+interface RadioGroupProps {
+  value?: string
+  defaultValue?: string
+  onValueChange?: (value: string) => void
+  disabled?: boolean
+  orientation?: "horizontal" | "vertical"
+  className?: string
+  children?: React.ReactNode
+}
+
+function RadioGroup({ className, value, defaultValue, onValueChange, orientation, children, ...props }: RadioGroupProps) {
   return (
-    <RadioGroupPrimitive
+    <Radio.Group
       data-slot="radio-group"
-      className={cn("grid gap-2", className)}
+      value={value}
+      defaultValue={defaultValue}
+      onChange={(val) => onValueChange?.(val)}
+      className={className}
+      {...props}
+    >
+      <div style={{ display: 'flex', flexDirection: orientation === 'horizontal' ? 'row' : 'column', gap: 'var(--mantine-spacing-sm)' }}>
+        {children}
+      </div>
+    </Radio.Group>
+  )
+}
+
+interface RadioGroupItemProps {
+  value: string
+  label?: string
+  disabled?: boolean
+  className?: string
+  labelClassName?: string
+  id?: string
+}
+
+function RadioGroupItem({ className, label, id, disabled, value, ...props }: RadioGroupItemProps) {
+  return (
+    <Radio
+      id={id}
+      data-slot="radio-group-item"
+      value={value}
+      label={label}
+      disabled={disabled}
+      className={className}
+      size="sm"
       {...props}
     />
   )
 }
 
-interface RadioGroupItemProps extends Radio.Root.Props {
-  label?: string
-  className?: string
-  labelClassName?: string
-}
-
-function RadioGroupItem({ className, label, id, labelClassName, ...props }: RadioGroupItemProps) {
-  const internalId = React.useId()
-  const itemId = id ?? internalId
-
-  return (
-    <div className="flex items-center gap-2">
-      <Radio.Root
-        id={itemId}
-        data-slot="radio-group-item"
-        className={cn(
-          "aspect-square size-4 rounded-full border border-input bg-transparent transition-colors outline-none",
-          "focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50",
-          "data-checked:border-primary",
-          "disabled:pointer-events-none disabled:opacity-50",
-          className
-        )}
-        {...props}
-      >
-        <Radio.Indicator
-          data-slot="radio-group-indicator"
-          className="flex items-center justify-center"
-        >
-          <span className="block size-2 rounded-full bg-primary" />
-        </Radio.Indicator>
-      </Radio.Root>
-      {label && (
-        <label
-          htmlFor={itemId}
-          data-slot="radio-group-label"
-          className={cn("text-sm font-medium leading-none cursor-pointer select-none", labelClassName)}
-        >
-          {label}
-        </label>
-      )}
-    </div>
-  )
-}
-
 export { RadioGroup, RadioGroupItem }
 export type { RadioGroupItemProps }