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/accordion.tsx

@@ -1,7 +1,5 @@
 import * as React from "react"
-import { Collapsible as CollapsiblePrimitive } from "@base-ui/react/collapsible"
-import { ChevronDownIcon } from "lucide-react"
-import { cn } from "../core/cn"
+import { Accordion as MantineAccordion } from "@mantine/core"
 
 interface AccordionItem {
   value: string
@@ -19,61 +17,72 @@ interface AccordionProps {
   children?: React.ReactNode
 }
 
-function Accordion({ className, children, ...props }: React.ComponentProps<"div"> & AccordionProps) {
+function Accordion({ className, type, defaultValue, children }: AccordionProps) {
+  if (type === "multiple") {
+    return (
+      <MantineAccordion
+        multiple
+        data-slot="accordion"
+        className={className}
+        defaultValue={Array.isArray(defaultValue) ? defaultValue : undefined}
+      >
+        {children}
+      </MantineAccordion>
+    )
+  }
+
   return (
-    <div data-slot="accordion" className={cn("divide-y divide-border", className)} {...props}>
+    <MantineAccordion
+      data-slot="accordion"
+      className={className}
+      defaultValue={typeof defaultValue === "string" ? defaultValue : undefined}
+    >
       {children}
-    </div>
+    </MantineAccordion>
   )
 }
 
-interface AccordionItemProps extends CollapsiblePrimitive.Root.Props {
+interface AccordionItemProps {
+  value: string
   className?: string
+  children?: React.ReactNode
+  disabled?: boolean
 }
 
-function AccordionItem({ className, ...props }: AccordionItemProps) {
+function AccordionItem({ className, value, children, ...props }: AccordionItemProps) {
   return (
-    <CollapsiblePrimitive.Root
+    <MantineAccordion.Item
       data-slot="accordion-item"
-      className={cn("group/accordion-item", className)}
-      {...props}
-    />
-  )
-}
-
-function AccordionTrigger({ className, children, ...props }: CollapsiblePrimitive.Trigger.Props) {
-  return (
-    <CollapsiblePrimitive.Trigger
-      data-slot="accordion-trigger"
-      className={cn(
-        "flex w-full items-center justify-between py-4 text-sm font-medium transition-all outline-none",
-        "hover:underline focus-visible:ring-3 focus-visible:ring-ring/50 focus-visible:underline",
-        "disabled:pointer-events-none disabled:opacity-50",
-        "[&[data-open]>svg]:rotate-180",
-        className
-      )}
+      value={value}
+      className={className}
       {...props}
     >
       {children}
-      <ChevronDownIcon className="size-4 shrink-0 text-muted-foreground transition-transform duration-200" />
-    </CollapsiblePrimitive.Trigger>
+    </MantineAccordion.Item>
   )
 }
 
-function AccordionContent({ className, children, ...props }: CollapsiblePrimitive.Panel.Props) {
+function AccordionTrigger({ className, children, ...props }: { className?: string; children?: React.ReactNode }) {
   return (
-    <CollapsiblePrimitive.Panel
-      data-slot="accordion-content"
-      className={cn(
-        "overflow-hidden text-sm",
-        "data-open:animate-in data-open:fade-in-0",
-        "data-closed:animate-out data-closed:fade-out-0",
-        className
-      )}
+    <MantineAccordion.Control
+      data-slot="accordion-trigger"
+      className={className}
       {...props}
     >
-      <div className="pb-4">{children}</div>
-    </CollapsiblePrimitive.Panel>
+      {children}
+    </MantineAccordion.Control>
+  )
+}
+
+function AccordionContent({ className, children, ...props }: { className?: string; children?: React.ReactNode }) {
+  return (
+    <MantineAccordion.Panel
+      data-slot="accordion-content"
+      className={className}
+      {...props}
+    >
+      {children}
+    </MantineAccordion.Panel>
   )
 }