[FEATURE]: Package with other MCP server in stdio mode

[yang-joseph]

The current way of integrating MCP in stdio mode is to wrap the stdio into a SSE listener. It requires another pod to run. If the original MCP supports streamHTTP, then the wrapper is really NOT necessary. Can mcp-context-forge allow adding an MCP server running in the same container as a subprocess using stdio? just like configuring a stdio MCP in cursor as follows (https://github.com/instana/mcp-instana?tab=readme-ov-file#stdio-mode-1):

{
  "servers": {
    "Instana MCP Server": {
      "command": "mcp-instana",
      "args": ["--transport", "stdio"],
      "env": {
        "INSTANA_BASE_URL": "https://your-instana-instance.instana.io",
        "INSTANA_API_TOKEN": "your_instana_api_token"
      }
    }
  }
}

🧭 Type of Feature

Please select the most appropriate category:

• Enhancement to existing functionality
• New feature or capability
• New MCP-compliant server
• New component or integration
• Developer tooling or test improvement
• Packaging, automation and deployment (ex: pypi, docker, quay.io, kubernetes, terraform)
• Other (please describe below)

┌─────────────────────────────────────────────────────────────┐
│                     Local Machine                            │
│                                                              │
│  ┌────────────────────────────────────────────────────┐    │
│  │   MCP Context Forge Gateway (Python)               │    │
│  │   - Runs locally (not in Docker)                   │    │
│  │   - Port: 4444                                     │    │
│  │   - Manages MCP server connections                 │    │
│  │                                                     │    │
│  │   ┌──────────────────────────────────────┐        │    │
│  │   │  mcp-instana (Python)                │        │    │
│  │   │  - Runs from local folder via uv     │        │    │
│  │   │  - Embedded via stdio transport      │        │    │
│  │   │  - Connects to remote Instana API    │        │    │
│  │   └──────────────────────────────────────┘        │    │
│  └────────────────────────────────────────────────────┘    │
│                          │                                   │
│                          │ connects to                      │
│                          ▼                                   │
│  ┌────────────────────────────────────────────────────┐    │
│  │         Docker Containers                          │    │
│  │  ┌──────────────┐  ┌──────────────┐              │    │
│  │  │  PostgreSQL  │  │    Redis     │              │    │
│  │  │  Port: 5432  │  │  Port: 6379  │              │    │
│  │  └──────────────┘  └──────────────┘              │    │
│  │                                                    │    │
│  │  ┌──────────────┐  ┌──────────────┐              │    │
│  │  │   pgAdmin    │  │ Redis Insight│              │    │
│  │  │  Port: 5050  │  │  Port: 5540  │              │    │
│  │  └──────────────┘  └──────────────┘              │    │
│  └────────────────────────────────────────────────────┘    │
└─────────────────────────────────────────────────────────────┘
                          │
                          │ API calls
                          ▼
              ┌─────────────────────────┐
              │   Remote Instana API    │
              │  (your-tenant.instana.io)│
              └─────────────────────────┘