feat(dashboard): adiciona widgets movíveis e ocultáveis

- Cria SortableWidget com @dnd-kit para drag-and-drop
- Cria DashboardGridEditable com modo de edição
- Cria WidgetSettingsDialog para gerenciar visibilidade
- Cria server actions para persistir preferências

components/dashboard/sortable-widget.tsx

@@ -0,0 +1,47 @@
+"use client";
+
+import { cn } from "@/lib/utils";
+import { useSortable } from "@dnd-kit/sortable";
+import { CSS } from "@dnd-kit/utilities";
+import type { ReactNode } from "react";
+
+type SortableWidgetProps = {
+  id: string;
+  children: ReactNode;
+  isEditing: boolean;
+};
+
+export function SortableWidget({
+  id,
+  children,
+  isEditing,
+}: SortableWidgetProps) {
+  const {
+    attributes,
+    listeners,
+    setNodeRef,
+    transform,
+    transition,
+    isDragging,
+  } = useSortable({ id, disabled: !isEditing });
+
+  const style = {
+    transform: CSS.Transform.toString(transform),
+    transition,
+  };
+
+  return (
+    <div
+      ref={setNodeRef}
+      style={style}
+      className={cn(
+        "relative",
+        isDragging && "z-50 opacity-90",
+        isEditing && "cursor-grab active:cursor-grabbing",
+      )}
+      {...(isEditing ? { ...attributes, ...listeners } : {})}
+    >
+      {children}
+    </div>
+  );
+}