Refactor UI components for layout management and results display

- Replaced the `renderizar` function in `layouts.rs` with a new `view` function using Iced for a more modern UI approach.
- Introduced a new `view_secao_layouts` function to handle the display of saved layouts.
- Updated the `resultado.rs` file to use Iced for rendering the results screen, including buttons for actions and pagination controls.
- Created a new `selecionar_aba.rs` file for the selection of XLSX sheet tabs, implementing a preview feature.
- Removed old rendering functions and replaced them with Iced components for better performance and maintainability.
- Added design tokens in `design_tokens.json` for consistent styling across the application.
- Created a mockup HTML file to visualize the UI design.

src/ui/components/paginacao.rs

@@ -0,0 +1,23 @@
+use crate::ui::message::Message;
+use iced::widget::{button, row, text};
+use iced::Element;
+
+/// Renderiza controles de paginação reutilizáveis.
+pub fn controles_paginacao(
+    pagina_atual: usize,
+    total_paginas: usize,
+    msg_anterior: Message,
+    msg_proximo: Message,
+) -> Element<'static, Message> {
+    let btn_anterior = button("◀").on_press_maybe((pagina_atual > 0).then_some(msg_anterior));
+    let btn_proximo =
+        button("▶").on_press_maybe((pagina_atual + 1 < total_paginas).then_some(msg_proximo));
+
+    row![
+        btn_anterior,
+        text(format!("Página {} / {}", pagina_atual + 1, total_paginas)).size(13),
+        btn_proximo,
+    ]
+    .spacing(8)
+    .into()
+}