v1.3.0 — SearXNG meta-search, search_web MCP tool, Langfuse v3 observability

- SearXNG self-hosted meta-search at /searxng/ (SEARXNG=1)
- search_web MCP tool — any function-calling model can search the web
- Langfuse v3 LLM observability at /langfuse/ (LANGFUSE=1)
  → requires ClickHouse (added automatically with langfuse profile)
- Langfuse traces all LiteLLM requests via success/failure callbacks
- 29 services, 99 models, 21 tools