chore(DC-168): record grade B (round 16) in changelog

urn:ump:ejzlob2bde6m6ivxfpgidmwu5a62pvl4wddm4iav7mwfuyfogirq

CHANGELOG.md

@@ -9,6 +9,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **DC-168 judge: grade B (round 16)** urn:ump:ejzlob2bde6m6ivxfpgidmwu5a62pvl4wddm4iav7mwfuyfogirq
+- **DC-168: calendar widget UX + theming.** Chip shows "No upcoming
+  appointments" (muted) when the connected calendar is empty; with events it
+  shows the next appointment with a highlighted day/time span. Modal gains a
+  month grid (prev/next nav, appointment days accent-tinted, today ring,
+  per-event time dots) plus the upcoming list (ended events excluded,
+  ongoing included). Universal theme contrast: chip colors derive via
+  color-mix from --accent (lighten on dark surfaces via html.light-bg,
+  darken on light) — WCAG >= 4.5:1 verified against all 10 builtin themes
+  (worst 4.60:1). Month-following fetch with disjoint-interval coverage
+  tracking; window-authoritative event cache (calendar-cache.js, uid+start
+  keys) so deletions/reschedules propagate on refetch; chip always renders
+  from the now-window even with a navigated viewMonth. 23 calendar tests.
 - **DC-167 judge: grade B (round 11)** urn:ump:kfn7m6vzd4ias2u5ghg62hvoug3j2y2gmturnytdz4g4od35hx4a
 - **DC-167: CalDAV default-namespace multistatus fix (Radicale silent
   zero-events).** extractCalendarsAndEvents required a namespace prefix on