I have an Elasticsearch service running locally that I need to explore for index integration.

**Connection Details:**
- Host: localhost (or elasticsearch if inside Docker)
- Port: 9200
- Index name: web_content
- No authentication required (development mode)

**Task:**
1. Connect to the Elasticsearch service at http://localhost:9200
2. Get the index mapping/schema for the `web_content` index
3. Retrieve one random document from the index with ALL its fields
4. Display the full document JSON with all available properties
5. Summarize what fields are available and their types

**Commands to help you:**
```bash
# Check ES is running
curl -s http://localhost:9200/_cluster/health

# Get index mapping
curl -s http://localhost:9200/web_content/_mapping

# Get a sample document with all fields
curl -s "http://localhost:9200/web_content/_search?size=1" -H "Content-Type: application/json" -d '{"query": {"function_score": {"query": {"match_all": {}}, "random_score": {}}}}'

# Get index stats (document count, size)
curl -s http://localhost:9200/web_content/_stats


Context:
This index contains crawled web content including:

HTML pages
PDF documents
OJS (Open Journal Systems) academic articles
I want to understand the document structure so I can integrate this index with arabic_research  index. Please show me the complete schema and a real sample document.