Add a collapse/expand-all toggle to the pedigree

A header button folds the whole tree down to just the dog or opens every
branch at once, alongside the per-dog toggles. Grouped with the zoom
controls, which the header now wraps on narrow screens.

src/style.css

@@ -1065,9 +1065,17 @@ section.collapsed > :not(h2) { display: none; }
   gap: 10px;
   padding: 12px 4px 8px;
 }
+.pedigree-header { flex-wrap: wrap; }
 .pedigree-header h1 { font-size: 1.4rem; }
-.ped-zoom {
+.ped-controls {
   margin-left: auto;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  flex-shrink: 0;
+}
+#ped-foldall { padding: 5px 10px; font-size: 0.8rem; white-space: nowrap; }
+.ped-zoom {
   display: flex;
   align-items: center;
   gap: 4px;