Show session lengths in ten categories

The Focus view grouped sessions into six buckets, too coarse to see a
rhythm. There are now ten: under 5m, 5-15m, 15-25m, 25-45m, 45m-1h,
1h-1h30m, 1h30m-2h, 2-3h, 3-4h and 4h or more. 25 minutes is a classic
pomodoro, and the long end separates 3-4h stretches from 4h+ hyperfocus.

Ten labelled columns don't fit side by side, so the chart is now drawn
with horizontal bars: every label stays readable at any width.

The buckets are one constant (analysis::focus::SESSION_BUCKETS); a new
test pins down where sessions land, including an exact boundary.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/ui/screens/insights.rs

@@ -12,7 +12,7 @@ use jiff::civil::{Date, Weekday};
 use jiff::{SignedDuration, ToSpan};
 use ratatui::Frame;
 use ratatui::crossterm::event::{MouseButton, MouseEvent, MouseEventKind};
-use ratatui::layout::{Constraint, Layout, Position, Rect};
+use ratatui::layout::{Constraint, Direction, Layout, Position, Rect};
 use ratatui::style::{Modifier, Style};
 use ratatui::symbols::Marker;
 use ratatui::text::{Line, Span};
@@ -375,14 +375,16 @@ impl Insights {
                     .style(Style::new().fg(ctx.theme.working))
             })
             .collect();
-        let bar_width = (chart_area.width.saturating_sub(2) / SESSION_BUCKETS.len() as u16)
-            .saturating_sub(2)
-            .clamp(3, 12);
+        // Horizontal bars, one row each, so every label fits; a blank row
+        // between bars when there's room.
+        let rows = chart_area.height.saturating_sub(2);
+        let gap = u16::from(rows >= 2 * SESSION_BUCKETS.len() as u16 - 1);
         frame.render_widget(
             BarChart::new(bars)
+                .direction(Direction::Horizontal)
                 .block(section(" How long your sessions last ", ctx))
-                .bar_width(bar_width)
-                .bar_gap(2)
+                .bar_width(1)
+                .bar_gap(gap)
                 .value_style(Style::new().fg(ratatui::style::Color::Black).bg(ctx.theme.working)),
             chart_area,
         );