remove SearXNG entirely; fix Kiwix cold-start

SearXNG:
- Dropped from both setup scripts and docker-compose (Google/Startpage
  block self-hosted instances by IP — not reliable enough to include)
- Removed all interactive safe-search and engine-selection prompts
- Removed Open WebUI RAG web-search env vars (ENABLE_RAG_WEB_SEARCH,
  SEARXNG_QUERY_URL, etc.)
- Removed port 8888 from UFW rules, start.sh URLs, done output, and
  the Caddyfile template
- Removed searxng/ from .gitignore (directory no longer created)
- configure-searxng-safesearch.sh kept in repo for optional manual use

Kiwix:
- Replace the blocking wait-loop (`until ls *.zim`) with a one-liner
  that passes whatever ZIM files exist (or none) directly to kiwix-serve,
  so the container starts immediately and shows an empty library page
  rather than hanging until ZIMs are downloaded

https://claude.ai/code/session_012gDnantBmFTWZGCiKyjazx

.gitignore

@@ -21,4 +21,3 @@ gitea/
 portainer-data/
 invokeai-data/
 invokeai-outputs/
-searxng/