Add MCP server with bearer-token auth and Claude integration docs

[Copilot]

Adds authentication to the MCP server and documents how to use it with Claude.

Bearer-token authentication

• BearerTokenVerifier implementing the MCP SDK TokenVerifier protocol, verified against a pre-shared secret
• Token via --auth-token flag or FCLI_MCP_AUTH_TOKEN env var
• Only applies to network transports (sse/streamable-http); ignored for stdio
• Auto-constructs AuthSettings when a verifier is present (required by FastMCP)

README: MCP Server section

• CLI options reference table
• Auth configuration examples
• Claude Code and Claude Desktop integration instructions
• All 16 available tools listed

Usage

# Start with auth
fcli-mcp --topo-file lab.clab.yml --transport sse --auth-token secret123

# Add to Claude Code (stdio, no auth needed)
claude mcp add fcli -- fcli-mcp --topo-file /path/to/lab.clab.yml

Tests

5 new tests covering BearerTokenVerifier (valid/invalid/empty token) and _build_server auth wiring.

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.