Calendar · Months: a month view, a year view, event chips and cards

CalendarMonthView lays a month in week rows. An event across days lies
over them as a bar in the first free lane, cut at the week's edge;
the rest sit by the hour as chips, and a crowded day keeps the rest
behind "N more". Arrows move a day, Page keys turn the month, and
Enter or a double press opens the day; the cursor holds through the
owner's echo of a turn. Days sit at sevenths of their row, as the bars
do, so text never widens a column.

YearView shows twelve small months; a day with something on it wears a
dot in its first event's hue. EventChip is an event in a line and
EventCard a block with its hours and place. MiniCalendar points to
forms::Calendar. Palette::hue is now the one home for a chart color by
index, for mail labels and events alike.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/theme/calendar.rs

@@ -0,0 +1,24 @@
+use gpui::Rems;
+
+use super::{Theme, tokens::px_to_rems};
+
+/// Calendar's measures.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct CalendarSizes {
+    /// An event's chip in a day, tall.
+    pub chip: Rems,
+    /// Rows of events a month's day holds under its number.
+    pub day_rows: usize,
+    /// A day in a year's small months, square.
+    pub mini_day: Rems,
+}
+
+impl Theme {
+    pub fn calendar(&self) -> CalendarSizes {
+        CalendarSizes {
+            chip: px_to_rems(20.0),
+            day_rows: 3,
+            mini_day: px_to_rems(28.0),
+        }
+    }
+}