feat: integrar painel de listas no painel de tarefas

- Remove Focus::Tabs, tabs das listas passam para dentro do painel esquerdo
- Layout simplificado: top area eliminada, body/calendar/status apenas
- Navegação entre listas com ←/→ no foco TaskList
- Tabs dinâmicas: separador '|', alinhamento à esquerda,
  número variável conforme largura do terminal
- Indicadores ' < ' e '>>' para overflow horizontal
- Scroll horizontal (list_tabs_scroll) com clamping automático

src/ui/components.rs

@@ -4,7 +4,7 @@ use chrono::Datelike;
 
 use ratatui::style::{Color, Modifier, Style};
 use ratatui::text::{Line, Span, Text};
-use ratatui::widgets::{Block, Borders, Clear, List, ListItem, Paragraph, Tabs, Wrap};
+use ratatui::widgets::{Block, Borders, Clear, List, ListItem, Paragraph, Wrap};
 use ratatui::layout::{Alignment, Constraint, Direction, Layout, Rect};
 use ratatui::Frame;
 
@@ -12,7 +12,6 @@ use crate::domain::models::*;
 use crate::app::SyncStats;
 use super::NetworkStatus;
 
-const TAB_COLOR: Color = Color::Cyan;
 const FOCUS_COLOR: Color = Color::Yellow;
 const SELECTED_COLOR: Color = Color::Green;
 const DETAIL_COLOR: Color = Color::White;
@@ -22,37 +21,6 @@ const STATUS_SYNC: Color = Color::Yellow;
 const POPUP_BG: Color = Color::Black;
 const POPUP_BORDER: Color = Color::Cyan;
 
-pub fn render_tabs_bar(
-    frame: &mut Frame,
-    area: Rect,
-    lists: &[TaskList],
-    selected: usize,
-    focused: bool,
-) {
-    let tab_titles: Vec<&str> = lists.iter().map(|l| l.title.as_str()).collect();
-
-    let block = Block::default()
-        .borders(Borders::ALL)
-        .border_style(Style::default().fg(if focused { FOCUS_COLOR } else { TAB_COLOR }))
-        .title(" Lists ")
-        .title_alignment(Alignment::Left);
-
-    let tabs = if tab_titles.is_empty() {
-        Tabs::new(vec![Line::from(" No lists ")])
-            .block(block)
-            .highlight_style(Style::default().add_modifier(Modifier::BOLD))
-            .select(selected)
-    } else {
-        Tabs::new(tab_titles.into_iter().map(|t| Line::from(Span::raw(t))).collect::<Vec<_>>())
-            .block(block)
-            .divider(Span::raw(" | "))
-            .highlight_style(Style::default().fg(FOCUS_COLOR).add_modifier(Modifier::BOLD))
-            .select(selected)
-    };
-
-    frame.render_widget(tabs, area);
-}
-
 fn relative_due_str(due: chrono::NaiveDateTime) -> (String, Color) {
     let now = chrono::Local::now().naive_local();
     let diff = due - now;
@@ -74,6 +42,9 @@ fn relative_due_str(due: chrono::NaiveDateTime) -> (String, Color) {
 pub fn render_task_list(
     frame: &mut Frame,
     area: Rect,
+    lists: &[TaskList],
+    selected_list: usize,
+    list_tabs_scroll: usize,
     tasks: &[Task],
     selected: usize,
     focused: bool,
@@ -84,7 +55,26 @@ pub fn render_task_list(
     let done = tasks.iter().filter(|t| t.status == TaskStatus::Completed).count();
     let todo = total - done;
 
-    let content_width = (area.width as usize).saturating_sub(5);
+    let block = Block::default()
+        .borders(Borders::ALL)
+        .border_style(Style::default().fg(if focused { FOCUS_COLOR } else { Color::DarkGray }))
+        .title(format!(" Tasks ({} todo / {} done) ", todo, done))
+        .title_alignment(Alignment::Left);
+
+    let inner = block.inner(area);
+    frame.render_widget(&block, area);
+
+    let inner_split = Layout::default()
+        .direction(Direction::Vertical)
+        .constraints([Constraint::Length(3), Constraint::Min(0)])
+        .split(inner);
+
+    let tabs_area = inner_split[0];
+    let tasks_area = inner_split[1];
+
+    render_list_tabs(frame, tabs_area, lists, selected_list, list_tabs_scroll, focused);
+
+    let content_width = (tasks_area.width as usize).saturating_sub(1);
 
     let items: Vec<ListItem> = tasks
         .iter()
@@ -160,14 +150,8 @@ pub fn render_task_list(
         })
         .collect();
 
-    let block = Block::default()
-        .borders(Borders::ALL)
-        .border_style(Style::default().fg(if focused { FOCUS_COLOR } else { Color::DarkGray }))
-        .title(format!(" Tasks ({} todo / {} done) ", todo, done))
-        .title_alignment(Alignment::Left);
-
     let list = List::new(items)
-        .block(block)
+        .block(Block::default())
         .highlight_style(
             Style::default()
                 .bg(if focused { Color::DarkGray } else { Color::Black })
@@ -176,7 +160,73 @@ pub fn render_task_list(
         )
         .highlight_symbol(">> ");
 
-    frame.render_stateful_widget(list, area, &mut ratatui::widgets::ListState::default().with_selected(Some(selected)));
+    frame.render_stateful_widget(list, tasks_area, &mut ratatui::widgets::ListState::default().with_selected(Some(selected)));
+}
+
+fn render_list_tabs(
+    frame: &mut Frame,
+    area: Rect,
+    lists: &[TaskList],
+    selected_list: usize,
+    scroll: usize,
+    focused: bool,
+) {
+    if lists.is_empty() || area.width < 4 {
+        return;
+    }
+
+    let max_width = area.width as usize;
+    let mut spans: Vec<Span> = Vec::new();
+
+    let mut used = if scroll > 0 {
+        spans.push(Span::styled(" <", Style::default().fg(Color::DarkGray)));
+        2
+    } else {
+        spans.push(Span::raw(" "));
+        1
+    };
+
+    let mut last_idx = scroll.wrapping_sub(1);
+    for i in scroll..lists.len() {
+        let title = &lists[i].title;
+        let title_len = title.chars().count();
+        let need_sep = if i > scroll { 3 } else { 0 };
+        let tab_space = title_len + 2;
+
+        if used + need_sep + tab_space > max_width {
+            break;
+        }
+
+        if need_sep > 0 {
+            spans.push(Span::raw(" | "));
+            used += 3;
+        }
+
+        let is_selected = i == selected_list;
+        let style = if is_selected && focused {
+            Style::default().fg(FOCUS_COLOR).add_modifier(Modifier::BOLD)
+        } else if is_selected {
+            Style::default().fg(FOCUS_COLOR)
+        } else {
+            Style::default().fg(Color::Cyan)
+        };
+
+        spans.push(Span::styled(format!(" {} ", title), style));
+        used += title_len + 2;
+        last_idx = i;
+    }
+
+    if last_idx + 1 < lists.len() && used + 5 <= max_width {
+        spans.push(Span::raw(" | "));
+        spans.push(Span::styled(">>", Style::default().fg(Color::DarkGray)));
+    }
+
+    if used < max_width {
+        spans.push(Span::raw(" ".repeat(max_width - used)));
+    }
+
+    let paragraph = Paragraph::new(Line::from(spans));
+    frame.render_widget(paragraph, area);
 }
 
 pub fn render_detail(