Make the food chart y-axis much finer

The grams axis now targets ~10 segments instead of ~4, so a 240 g day
gets 25 g gridlines; steps stay round numbers at any scale.

src/app.js

@@ -873,9 +873,10 @@
 
   // Grams axis: 0-based with a "nice" step so tick labels stay round whatever
   // the daily totals are (tens of grams for a tiny puppy, hundreds+ later).
+  // Aims for ~10 segments so day-to-day differences of a few grams show.
   function niceAxisGrams(rawMax) {
-    if (!(rawMax > 0)) return { yMax: 100, steps: 2 };
+    if (!(rawMax > 0)) return { yMax: 100, steps: 4 };
-    const rawStep = rawMax / 4;
+    const rawStep = rawMax / 10;
     const mag  = Math.pow(10, Math.floor(Math.log10(rawStep)));
     const norm = rawStep / mag;
     const step = (norm <= 1 ? 1 : norm <= 2 ? 2 : norm <= 2.5 ? 2.5 : norm <= 5 ? 5 : 10) * mag;

src/changelog.json

@@ -1,4 +1,5 @@
 [
+  { "date": "2026-07-13", "text": "Much finer y-axis on the food chart" },
   { "date": "2026-07-13", "text": "The awake/asleep timer is bigger and sits first in the top bar" },
   { "date": "2026-07-13", "text": "The sleep, daily counts and food charts now cover the last 14 days instead of 7" },
   { "date": "2026-07-13", "text": "The awake/asleep timer lives in the frozen top bar" },