Interleave the sleep and wake lists, move walks down

Sleep windows and Wake windows were two panels showing two halves of one
sequence: a wake window is precisely the gap between two sleeps, so the panels
alternated with each other and neither could be read as the day's rhythm on its
own. Answering "how long was he up before that nap?" meant looking at one panel,
holding a time in your head, and finding it in the other.

They are one list now, the two window sets sorted together by start time, which
is all the interleaving that alternating-by-construction needs. Each row states
whether it is asleep or awake and carries a stripe in its colour, so the
alternation reads before the words do, and the row still running keeps the
highlight it had. renderWindowList grew the ability for a window to bring its
own class and label; the single-kind lists still pass one of each for the whole
list and tag only the open row, where "Walking" is news rather than a repeat of
the heading it sits under.

One rule had to be spelled out: the new per-kind stripe ties on specificity with
the generic .ww.ongoing, and being later would have won, leaving an open awake
row with a faded edge instead of its full-strength one.

The walks group — the panel and both its patterns — moves below "Pees, poos &
meals". The three stay together: they were grouped under Walks deliberately, and
leaving the patterns behind would strand two walk charts among the sleep ones.

Both old panel keys go stale, so anyone who had folded Sleep windows or Wake
windows gets the merged panel open, as with any panel that is new to a build.

src/changelog.json

@@ -1,4 +1,6 @@
 [
+  { "date": "2026-08-31", "text": "The Walks panel and its two charts have moved down the page, below “Pees, poos & meals”" },
+  { "date": "2026-08-31", "text": "Sleep windows and Wake windows are one “Sleep & wake” panel now, with the two interleaved into a single list in time order — asleep 22:10–06:05, awake until 08:30, asleep 45 min, and so on down the day. A wake window is just the gap between two sleeps, so the two lists were always halves of the same sequence, and reading them in order makes “only a 45-minute nap after two and a half hours up” obvious in a way two separate lists never did. Each row says which it is and carries a stripe in its colour; whichever one is still running keeps the highlight" },
   { "date": "2026-08-31", "text": "The list of weigh-ins under the Weight chart folds away on its own now — tap “History” inside the panel to collapse just the rows and keep the latest figure and the curve on screen. It remembers the choice like the panels do, and folding the whole Weight panel still takes everything with it" },
   { "date": "2026-08-31", "text": "Walks now get the same two pattern views sleep has. “When … walks” is a day-per-row grid shaded where a walk was on, so you can see at a glance whether the routine is actually regular or drifts around. “Walk trend” draws the minutes walked so far at each point of the day against yesterday and the average over the picked window, with the age-based goal as a line and a ✓ once the day clears it — the line climbs only while a walk is on, so every step is one walk. Both appear under the Walks panel as soon as you have logged a walk, and stay out of the way until then" },
   { "date": "2026-08-31", "text": "The 7d / 14d / 30d buttons now set the window for the Timing panel too. Until now the typical, shortest and longest gaps between pees, poos and meals were always measured over the last 7 days whatever you picked; switch to 30d and they are measured over 30, which settles down the typical gap once there is a month of history to draw on" },