fix(maps): bound place-photo cache growth (Wikimedia + Google) (#1174)

The place-photo cache (uploads/photos/google) grew unbounded: a Wikimedia
geosearch path cached full-res originals despite requesting a 400px thumb,
the writer applied no size guard, nothing reclaimed orphaned files, and
backups archived the whole re-derivable cache verbatim.

- Prefer the scaled `thumburl` over the full-res `info.url` in the Commons
  geosearch fallback.
- Downscale any cached image to <=800px JPEG via the existing jimp dep,
  with a safe fallback to the original bytes on decode failure.
- Add sweepOrphans() (orphaned meta rows + stray files) wired into the
  scheduler (startup + nightly), and removeIfUnreferenced() called on
  place delete for prompt reclamation.
- Exclude the re-derivable photo/trek caches from backups; restores
  self-heal as the cache dirs are recreated at startup.

server/src/index.ts

@@ -79,6 +79,7 @@ const onListen = () => {
   scheduler.startDemoReset();
   scheduler.startIdempotencyCleanup();
   scheduler.startTrekPhotoCacheCleanup();
+  scheduler.startPlacePhotoCacheCleanup();
   scheduler.startAirTrailSync();
   const { startTokenCleanup } = require('./services/ephemeralTokens');
   startTokenCleanup();