Keep the header and weight rows tidy when the age is long

The age counter can read "16 weeks (3 months and 3 weeks) old", which broke
two tight layouts: the header title never truncated, so a long name (or the
wide status pill) collided with the action buttons and the age wrapped to
three lines; and each weight-log row embedded the full age, wrapping to two
lines.

Add compact age formatters and use them where space is tight: formatAgeShort
("16 wk · 3 mo 3 wk") in the header, formatAgeWeeks ("16 wk") in weight rows;
the verbose form stays on the roomy weight-chart caption. Make the header
robust — the title flexes and the name ellipsis-truncates so the buttons are
never pushed, while the age wraps rather than truncating so it's never cut
off. Weight rows keep the date/age on one line with the value pinned right.

src/changelog.json

@@ -1,4 +1,5 @@
 [
+  { "date": "2026-08-01", "text": "Tidied the header on long names and ages — the name now truncates instead of shoving the buttons, and the age reads as a compact \"16 wk · 3 mo 3 wk\"; weight-log rows are a single line again (\"Aug 1 · 16 wk\")" },
   { "date": "2026-07-26", "text": "Added a fan-chart view of the pedigree (toggle it in the header): your dog at the centre with each generation fanning outward as a ring, so many generations fit at once without the tree sprawling sideways — tap a wedge for that dog, and repeated ancestors keep their colour" },
   { "date": "2026-07-26", "text": "Added a Collapse all / Expand all toggle to the pedigree, to fold the whole tree down to your dog or open every branch at once" },
   { "date": "2026-07-26", "text": "The pedigree is now zoomable — use the +/− buttons, ⌘/Ctrl-scroll, or pinch on a phone — to fit a wide tree on screen or zoom in for detail; your zoom level is remembered" },