feat(tui): tambah dan pasang sidebar dashboard permanen

Sidebar kanan permanen (Workflow/Tasks/Usage) menggantikan panel todo
ad-hoc yang lama. Widget baca state yang sudah ada, tidak ada perubahan
skema AppStateRest.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/view/mod.rs

@@ -9,6 +9,7 @@
 
 pub mod chat;
 pub mod markdown;
+pub mod sidebar;
 pub mod status;
 pub mod theme;
 pub mod workflow;
@@ -20,14 +21,21 @@ use ratatui::widgets::{Block, Borders, Clear, Paragraph, Wrap};
 use ratatui::Frame;
 use theme::Theme;
 
+/// Minimum terminal width (columns) at which the persistent dashboard
+/// sidebar is shown; below this, chat reclaims the full width.
+const SIDEBAR_MIN_WIDTH: u16 = 90;
+
 /// Top-level render entry point called once per TUI frame.
 pub fn draw(frame: &mut Frame, state: &crate::app::state::rest::AppStateRest) {
     let area = frame.area();
 
-    // ── Determine if we need a side panel (todo) ─────────────────────────
-    let show_todo = !state.misc.todo_content.is_empty()
-        || state.misc.overlay == crate::app::state::types::Overlay::Todo;
-    let (main_area, todo_area) = if show_todo && area.width > 60 {
+    // ── Determine if the terminal is wide enough for the persistent
+    //    dashboard sidebar (Workflow / Tasks / Usage). Below this, chat
+    //    reclaims the full width — same width-driven-collapse pattern the
+    //    old single-widget todo panel used, just with a wider threshold
+    //    since this sidebar holds three stacked widgets, not one.
+    let show_sidebar = area.width > SIDEBAR_MIN_WIDTH;
+    let (main_area, sidebar_area) = if show_sidebar {
         let h_chunks = Layout::default()
             .direction(Direction::Horizontal)
             .constraints([
@@ -55,9 +63,7 @@ pub fn draw(frame: &mut Frame, state: &crate::app::state::rest::AppStateRest) {
     let status_area = chunks[2];
 
     // ── Render main area (overlay or chat) ───────────────────────────────
-    if state.misc.overlay.is_active()
-        && state.misc.overlay != crate::app::state::types::Overlay::Todo
-    {
+    if state.misc.overlay.is_active() {
         let overlay = state.misc.overlay;
         render_overlay(frame, chat_area, overlay, state);
     } else {
@@ -70,9 +76,9 @@ pub fn draw(frame: &mut Frame, state: &crate::app::state::rest::AppStateRest) {
     // ── Status bar ───────────────────────────────────────────────────────
     status::draw_status_bar(frame, status_area, state);
 
-    // ── Todo side panel ──────────────────────────────────────────────────
-    if let Some(todo_rect) = todo_area {
-        render_todo_panel(frame, todo_rect, state);
+    // ── Dashboard sidebar ────────────────────────────────────────────────
+    if let Some(sidebar_rect) = sidebar_area {
+        sidebar::draw_sidebar(frame, sidebar_rect, state);
     }
 
     // ── Toasts (top-right floating) ──────────────────────────────────────
@@ -83,30 +89,6 @@ pub fn draw(frame: &mut Frame, state: &crate::app::state::rest::AppStateRest) {
 //  Panel helpers
 // ────────────────────────────────────────────────────────────────────────────
 
-fn render_todo_panel(
-    frame: &mut Frame,
-    area: Rect,
-    state: &crate::app::state::rest::AppStateRest,
-) {
-    let block = Block::default()
-        .title(" 📋 Tasks ")
-        .borders(Borders::ALL)
-        .border_style(Style::default().fg(Theme::ACCENT_PURPLE))
-        .style(Style::default().bg(Theme::BG));
-
-    let content = if state.misc.todo_content.is_empty() {
-        "  No tasks yet."
-    } else {
-        &state.misc.todo_content
-    };
-
-    let paragraph = Paragraph::new(content)
-        .block(block)
-        .wrap(Wrap { trim: false });
-
-    frame.render_widget(paragraph, area);
-}
-
 fn render_main_panel(
     frame: &mut Frame,
     area: Rect,
@@ -973,3 +955,58 @@ fn centered_rect(area: Rect, percent_x: u16, percent_y: u16) -> Rect {
         height: area.height.saturating_sub(y_pad * 2).max(10),
     }
 }
+
+/// Split `items` into the slice that fits within `max_visible` entries and
+/// the count of items hidden beyond that limit.
+///
+/// Used by sidebar widgets (Workflow, Tasks) to cap their content to the
+/// available panel height instead of overflowing it.
+///
+/// Return: `(visible_slice, hidden_count)` — `hidden_count` is `0` when
+/// everything fits.
+pub(crate) fn split_for_display<T>(items: &[T], max_visible: usize) -> (&[T], usize) {
+    if items.len() <= max_visible {
+        (items, 0)
+    } else {
+        (&items[..max_visible], items.len() - max_visible)
+    }
+}
+
+/// Build the dim trailing hint line a sidebar widget shows when its
+/// content is truncated, pointing at the slash command that opens the
+/// full "expand" overlay for that widget (e.g. `"/workflow"`, `"/todo"`).
+pub(crate) fn overflow_hint_line(hidden: usize, command: &str) -> Line<'static> {
+    Line::from(Span::styled(
+        format!(" +{hidden} more — {command}"),
+        Style::default().fg(Theme::TEXT_DIM).add_modifier(Modifier::ITALIC),
+    ))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn split_for_display_returns_everything_when_it_fits() {
+        let items = vec![1, 2, 3];
+        let (visible, hidden) = split_for_display(&items, 5);
+        assert_eq!(visible, &[1, 2, 3]);
+        assert_eq!(hidden, 0);
+    }
+
+    #[test]
+    fn split_for_display_truncates_and_counts_hidden() {
+        let items = vec![1, 2, 3, 4, 5];
+        let (visible, hidden) = split_for_display(&items, 2);
+        assert_eq!(visible, &[1, 2]);
+        assert_eq!(hidden, 3);
+    }
+
+    #[test]
+    fn overflow_hint_line_mentions_hidden_count_and_command() {
+        let line = overflow_hint_line(3, "/todo");
+        let text: String = line.spans.iter().map(|s| s.content.as_ref()).collect();
+        assert!(text.contains("+3 more"));
+        assert!(text.contains("/todo"));
+    }
+}