Add adjustable event age filtering to S2 GhostMaps

docs/CURRENT-STATE.md

@@ -5663,6 +5663,7 @@ request viewbox and continues searching without that geographic preference.
 
 - **What it shows.** Events ▸ **S2 GhostMaps** draws the current edition of S2 Underground's KMZ intel products from `github.com/s2underground/GhostMaps`. The products are the Common Intelligence Picture and the 30-day kinetic pull (both on by default), the Border Crisis Map, the Iran Common Intelligence Picture, Iran Kinetic Events, Yemen FLOT, and **Latest Drop**: the newest dated incident file outside those series, `0_Archive`, `Basedata` and `Reference Material`. Each product has a chip in the row. The chip choice is kept in `localStorage` (`gev.ghostmaps.products`) and falls back to the defaults when storage is blocked.
 - **Editions.** `src/layers/ghostMaps/catalog.js` (pure) matches whole repository paths per product. The newest edition wins by the date written in the file name, then by `Export_N`/`vN`. Undated names, such as the fixed 30-day file, are identified by blob sha. Files over 50 MiB are left out (the 62 MB census KMZ, for example). A renamed folder drops the product rather than matching elsewhere.
+- **Event age filter.** The same filter applies to every selected S2 product, including Border Crisis, Iran Picture, Iran Kinetic, Yemen FLOT and Latest Drop. S2 products default to seven days, with row buttons for 1, 3, 7, 14 or 30 days and **All markers**. The choice persists independently of product selection in `localStorage` (`gev.ghostmaps.ageDays`); missing, invalid or blocked storage uses seven days. Only the placemark's `Date of Event` (or `EventDate`/`Date`) determines its age, never report dates, dates in prose or KMZ edition/upload dates. Undated, blank or unparseable event dates and future dates stay visible. ArcGIS `M/D/YYYY` dates and optional AM/PM times, plus ISO dates/timestamps, are supported; values without a zone use UTC and date-only values use midnight UTC. The exact cutoff is included. Events age out every minute and during catalog updates, even without a new file or a successful catalog fetch. Widening the window or choosing All markers restores omitted events from the cached KMZ. Removed entities and selected cards disappear together; surviving pick ids stay stable. Product defaults and the update stream are unchanged.
 - **Updates.** The repository is not ours, so there is no webhook. `server/providers/ghostMaps.js` starts with the first `/api/ghostmaps` request, so an install that never enables the layer never contacts GitHub.
   - It reads the branch head from git's smart-HTTP ref advertisement (`/info/refs?service=git-upload-pack`, about 0.5 KB, outside the REST rate limit) every `GHOSTMAPS_POLL_SECONDS` (15 s by default, 5 s minimum). Failures back off from 15 s to 5 min.
   - Only a new head costs REST calls: one recursive tree and one commit. An optional `GITHUB_TOKEN` raises the REST limit.