Replace the big clock with a timer pill in the frozen day bar

The full-width asleep/awake card becomes a compact colored pill next to
the day controls: state emoji plus the live counter, with "since" moved
to the tooltip. One glance at the pinned bar now gives both the day and
the current state.

src/changelog.json

@@ -1,4 +1,5 @@
 [
+  { "date": "2026-07-13", "text": "The awake/asleep timer lives in the frozen top bar" },
   { "date": "2026-07-13", "text": "The day picker is a bar frozen at the top of the page" },
   { "date": "2026-07-13", "text": "Attach multiple photos to an event — the photo picker now also offers the gallery with multi-select" },
   { "date": "2026-07-13", "text": "Track food by weight: logging a meal asks for grams (optional), with a daily total in the overview and a weekly chart" },