Give walks the two sleep pattern views

Walks had the overview tile, the window list and minutes per day, but not the
two views that answer the questions sleep already answers: when in the day does
it actually happen, and is today keeping up.

"When … walks" is the sleep actogram drawn from walk windows, so the drawing
moves into drawActogram(svgId, windows, barCls) and both timelines become one
line each. Nothing about that picture was ever sleep-specific — it clips
windows to day rows and shades them — so the third caller costs nothing.

"Walk trend" is the sleep trend's shape with three deliberate differences.
Today and yesterday are built from their own walk boundaries rather than hourly
samples, so the steps stay square: a 30-minute walk is a step, not an hour-wide
ramp. The average keeps hourly sampling, since a mean over many days is a
smooth reference with no steps of its own to preserve. And there is no
projected tail — sleep is a state the puppy drifts back into, so continuing
today's line by what the average day adds is a fair guess, while walks are
decisions, and projecting them would be predicting the handler, not the dog.

The goal is a line, not a band: the five-minute rule gives one number to reach
with no upper bound a band would imply. With no projection to carry it, the ✓
that marks being on track goes on today's own chip.

The axis stays linear where the sleep trend stretches above 10h. That stretch
exists because sleep's interesting hours crowd a 16h goal; a walk total reads
the same at 10 minutes as at 60.

Both panels sit with the other walk views rather than beside their sleep twins,
following the grouping-by-subject the charts just moved to, and both hide
themselves until a walk exists so they cost nothing to anyone not logging them.

src/changelog.json

@@ -1,4 +1,5 @@
 [
+  { "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" },
   { "date": "2026-08-31", "text": "The charts are grouped by subject instead of all sharing one “Last 7 days” panel. Sleep hours per day is now its own Sleep panel, sitting just above the “When … sleeps” timeline with the rest of the sleep views. Daily counts and Food have joined the by-hour chart in one “Pees, poos & meals” panel, so how many a day, how much food went with them and what hours they fall in read together. Minutes walked per day has moved into the Walks panel. The 7d / 14d / 30d picker now sits in the Sleep panel and still sets the window for every one of these charts" },
   { "date": "2026-08-31", "text": "A sleep or walk pair is now tied together in the History log by a dotted rail down the side, in that pair's colour, running from the start row to the end row. Anything logged in between sits inside the bracket, so a pee taken on a walk reads as having happened during it. A pair still in progress, or one that ran over from yesterday, leaves its end of the rail open" },