Accept date shortcuts in the Work day field

Adding work to a day you forgot to track meant typing its full date.
The Work day field now also takes 09-14 (this year), today, yesterday,
-3 (three days ago) and weekday names like mon or friday (the most
recent one). The editor shows the date it understood next to the field.

The parsing lives in time::format::parse_date, next to parse_time.

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

src/ui/popups/segment_editor.rs

@@ -16,7 +16,7 @@ use ratatui::widgets::Paragraph;
 use super::{field_line, message_line, window};
 use crate::action::Action;
 use crate::domain::{Segment, WorkDay};
-use crate::time::format::parse_time;
+use crate::time::format::{parse_date, parse_time};
 use crate::time::resolve::{nearest, next_after};
 use crate::ui::keymap::{self, Binding, Command};
 use crate::ui::widgets::text_input::{InputEvent, TextInput};
@@ -88,11 +88,12 @@ impl SegmentEditor {
         }
     }
 
-    /// The work day the segment is filed under (the Work day field).
-    fn work_day(&self) -> Result<Date, String> {
+    /// The work day the segment is filed under (the Work day field, which
+    /// also takes shortcuts like "yesterday", "-3" or "mon").
+    fn work_day(&self, ctx: &Context) -> Result<Date, String> {
         match self.target {
             Target::Running { day, .. } => Ok(day),
-            _ => self.day.text().trim().parse().map_err(|_| "work day: write it like 2026-09-24".to_string()),
+            _ => parse_date(self.day.text(), ctx.now.date()).map_err(|error| format!("work day: {error}")),
         }
     }
 
@@ -122,7 +123,7 @@ impl SegmentEditor {
     }
 
     fn resolve(&self, ctx: &Context) -> Result<Resolved, String> {
-        let day = self.work_day()?;
+        let day = self.work_day(ctx)?;
         let start_time = parse_time(self.start.text()).map_err(|error| format!("start: {error}"))?;
         let start = nearest(start_time, &self.reference(day, ctx));
         let end = match self.end.text().trim() {
@@ -221,7 +222,11 @@ impl Component for SegmentEditor {
             ),
         ];
         if !self.is_running() {
-            let note = Span::styled("the day it counts for", ctx.theme.muted());
+            // Which date the field means ("yesterday" → Wed Sep 23).
+            let note = match self.work_day(ctx) {
+                Ok(day) => Span::styled(ctx.fmt.date_short(day), ctx.theme.accent()),
+                Err(_) => Span::styled("a date, yesterday, -3, mon...", ctx.theme.muted()),
+            };
             lines.push(field_line("Work day", &self.day, self.field == 2, self.inserting, note, ctx.theme));
         }
         lines.push(Line::default());