fix(ghostmaps): keep age-window changes consistent and make the age choice a switch

Review fixes on top of #1528:
- Narrowing the age window only removes markers; a product loaded with a
  narrower window is reloaded when the window widens again. Fixes markers
  missing after 7d -> 1d -> 7d and avoids reparsing every KMZ on narrowing.
- A wider window over the same edition keeps the open report card.
- Date-only event dates cover their whole UTC day, so 1d still shows
  yesterday's reports.
- The age options are one labelled "Event age" radio switch (row
  `segmented` control, as FIRMS confidence) instead of toggle chips mixed
  with the product chips.
- Un-nest the per-product age test; QA compares data-source counts with the
  live defaults instead of a hard-coded 2.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/i18n/locales/de.json

@@ -3171,5 +3171,6 @@
   "All markers": "Alle Markierungen",
   "Show markers of every age": "Markierungen jeden Alters anzeigen",
   "Maximum event age: {days}d; undated markers are kept": "Maximales Ereignisalter: {days} Tage; undatierte Markierungen bleiben",
+  "Event age": "Ereignisalter",
   "Event age: {days}d · undated kept": "Ereignisalter: {days} Tage · undatierte bleiben"
 }