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.md

@@ -6,14 +6,14 @@ domain: ui
 version: "1.0.0"
 purity: impure
 signature: "Accordion(props: AccordionProps): JSX.Element"
-description: "Secciones colapsables con animaciones. Base-UI Collapsible primitive. Composable: AccordionItem + AccordionTrigger + AccordionContent."
-tags: [accordion, collapsible, component, ui, interactive, base-ui]
-uses_functions: [cn_ts_core]
+description: "Secciones colapsables con animaciones. Mantine Accordion. Composable: AccordionItem + AccordionTrigger + AccordionContent."
+tags: [accordion, collapsible, component, ui, interactive, mantine]
+uses_functions: []
 uses_types: []
 returns: []
 returns_optional: false
 error_type: ""
-imports: ["@base-ui/react/collapsible", "lucide-react"]
+imports: ["@mantine/core"]
 output: "Componente Accordion que renderiza secciones colapsables con soporte para múltiples items abiertos simultáneamente"
 tested: false
 tests: []
@@ -33,14 +33,14 @@ variant: []
 ## Ejemplo
 
 ```tsx
-<Accordion>
-  <AccordionItem defaultOpen>
+<Accordion defaultValue="section-1">
+  <AccordionItem value="section-1">
     <AccordionTrigger>Seccion 1</AccordionTrigger>
     <AccordionContent>
       Contenido de la primera seccion.
     </AccordionContent>
   </AccordionItem>
-  <AccordionItem>
+  <AccordionItem value="section-2">
     <AccordionTrigger>Seccion 2</AccordionTrigger>
     <AccordionContent>
       Contenido de la segunda seccion.
@@ -51,4 +51,4 @@ variant: []
 
 ## Notas
 
-Cada AccordionItem es un Collapsible independiente — permite multiples items abiertos simultaneamente. Para exclusividad (solo uno abierto), manejar el estado externamente. El chevron rota 180 grados con [data-open]. Exports: Accordion, AccordionItem, AccordionTrigger, AccordionContent.
+Usa Mantine Accordion nativo. Soporta type single (default) y multiple para multiples items abiertos. El chevron se maneja automaticamente por Mantine. AccordionItem requiere prop value unico. Exports: Accordion, AccordionItem, AccordionTrigger, AccordionContent.