[Discovery] mcp/fetch - Web Content Fetching

## Project Association

This issue tracks the `mcp/fetch` MCP server in the core profile.

### Server Details
- **Name**: fetch
- **Source**: https://github.com/modelcontextprotocol/servers/tree/main/src/fetch
- **Docker Hub**: https://hub.docker.com/r/mcp/fetch
- **Category**: web
- **Language**: Python

### Transport Status
- **Current**: stdio only (upstream)
- **Implementation**: HTTP-wrapped via supergateway
- **Docker Image**: `fetch-mcp:http` (custom build)

### Tools Provided
- `fetch`: Fetches a URL and returns content as markdown
- Parameters: url (required), max_length, start_index, raw

### Docker Status
- Official image: `mcp/fetch`
- Custom wrapper: `fetch.dockerfile` (extends base with supergateway)
- HADOLint: Not checked

### Notes
- Python-based server using UV for dependency management
- Required extending base image (not multi-stage) due to UV symlink issues
- Works well with Traefik multi-layer routing

### Tracking
- [ ] Document all tools comprehensively
- [ ] HADOLint compliance check
- [ ] Consider Rust rewrite