feat: add complex MCP server commands support (#22)

* feat: add complex MCP server commands support

Add ServerConfig type with command, args, env, cwd fields and support
for multiple transport types (Stdio, HTTP, SSE).

Changes:
- Add ServerConfig with builder pattern in mcp-core
- Add TransportType enum (Stdio, Http, Sse)
- Update validation to check command, args, env separately
- Block dangerous env vars (LD_PRELOAD, DYLD_*, PATH)
- Update Introspector::discover_server to accept ServerConfig
- Update Bridge::connect to accept ServerConfig
- Update CLI commands to use new API

Closes #21

* chore: update dependencies

* docs(examples): update test_github with GitHub MCP server examples

Add multiple configuration options for GitHub MCP server:
- Docker: docker run -i --rm ghcr.io/github/github-mcp-server
- Remote: HTTP transport to api.githubcopilot.com
- Local: github-mcp-server stdio (build from source)

Demonstrate ServerConfig usage with args, env, and headers.

Author: bug-ops

.gitignore

@@ -1,6 +1,5 @@
 # Rust
 /target
-Cargo.lock
 **/*.rs.bk
 *.pdb