feat: parallelize audit repair and add nitro/SQL repair options

- Parallelize icon and nitro downloads in the audit repair with a
  sliding-window worker pool (6 concurrent) to speed up large catalogs
- Add repairMissingNitros: fetch missing .nitro bundles from configured
  nitro sources (Wibbo default), validating each bundle before writing
- Add catalog-repair service: generate/apply catalog_items SQL for furni
  missing a catalog entry and repair FurnitureData.json (add missing +
  dedupe classnames)
- Wire all options through the audit API and client UI with live progress
  and result stats (icons, nitros, SQL, furnidata)
- Add Wibbo as default nitro source alongside existing icon sources
- Ignore runtime furni assets downloaded into public/ during repair

.gitignore

@@ -24,5 +24,10 @@ gitea
 # Runtime uploaded media (persistent, outside public/)
 storage/
 
+# Runtime downloaded furni assets (mirrored from gamedata / audit repair)
+public/nitro-assets/bundled/furniture/
+public/swf/dcr/
+public/tmp/
+
 # Test coverage reports
 coverage/