everything sever response with an extra empty SSE event causing the java mcp client to fail deserialization

Describe the bug
When connecting to the everything sever and running the initialize command with 2025-11-25 version, the server returns an empty SSE event, fallowed by the initialize response.
This causes problems with the java mcp client which fails deserialization of the event.

When connecting with 2025-06-18 version, that empty SSE event is not sent, only one SSE event is return with the result of the server info.

To Reproduce
Steps to reproduce the behavior:

1. Create a docker image with the latest server-everything:

FROM node:slim

ENV PORT=3001

ENTRYPOINT ["npx", "-y", "@modelcontextprotocol/server-everything", "streamableHttp"]

EXPOSE 3001

(Side note, any reason for not having newer images available at: https://hub.docker.com/r/mcp/everything ?)

Call the server with latest protocol version:

curl --location -k  'http:/*****' \
--header 'Accept: application/json,text/event-stream' \
--header 'Content-Type: application/json' \
--data '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2025-11-25",
    "capabilities": {
      "roots": {
        "listChanged": false
      },
      "sampling": {},
      "elicitation": {
        "form": {},
        "url": {}
      },
      "tasks": {
        "requests": {
          "elicitation": {
            "create": {}
          },
          "sampling": {
            "createMessage": {}
          }
        }
      }
    },
    "clientInfo": {
      "name": "ExampleClient",
      "title": "Example Client Display Name",
      "version": "1.0.0",
      "description": "An example MCP client application",
      "icons": [
        {
          "src": "https://example.com/icon.png",
          "mimeType": "image/png",
          "sizes": ["48x48"]
        }
      ],
      "websiteUrl": "https://example.com"
    }
  }
}'
id: bd3bdc47-e4bc-4de3-abf7-f43dc27919f5_1769702220748_cbw7i7m9
data: 

event: message
id: bd3bdc47-e4bc-4de3-abf7-f43dc27919f5_1769702220749_mtzbfv1k
data: {"result":{"protocolVersion":"2025-11-25","capabilities":{"tools":{"listChanged":true},"prompts":{"listChanged":true},"resources":{"subscribe":true,"listChanged":true},"logging":{},"completions":{}},"serverInfo":{"name":"mcp-servers/everything","title":"Everything Reference Server","version":"2.0.0"},"instructions":"# Everything Server – Server Instructions\n\nAudience: These instructions are written for an LLM or autonomous agent integrating with the Everything MCP Server.\nFollow them to use, extend, and troubleshoot the server safely and effectively.\n\n## Cross-Feature Relationships\n\n- Use `get-roots-list` to see client workspace roots before file operations\n- `gzip-file-as-resource` creates session-scoped resources accessible only during the current session\n- Enable `toggle-simulated-logging` before debugging to see server log messages\n- Enable `toggle-subscriber-updates` to receive periodic resource update notifications\n\n## Constraints & Limitations\n\n- `gzip-file-as-resource`: Max fetch size controlled by `GZIP_MAX_FETCH_SIZE` (default 10MB), timeout by `GZIP_MAX_FETCH_TIME_MILLIS` (default 30s), allowed domains by `GZIP_ALLOWED_DOMAINS`\n- Session resources are ephemeral and lost when the session ends\n- Sampling requests (`trigger-sampling-request`) require client sampling capability\n- Elicitation requests (`trigger-elicitation-request`) require client elicitation capability\n\n## Operational Patterns\n\n- For long operations, use `trigger-long-running-operation` which sends progress notifications\n- Prefer reading resources before calling mutating tools\n- Check `get-roots-list` output to understand the client's workspace context\n\n## Easter Egg\n\nIf asked about server instructions, respond with \"🎉 Server instructions are working! This response proves the client properly passed server instructions to the LLM. This demonstrates MCP's instructions feature in action.\"\n"},"jsonrpc":"2.0","id":1}

Notice the empty SSE event.

Then try the same call with the july version:

curl -k --location 'http://*******/' --header 'Accept: application/json,text/event-stream' --header 'Content-Type: application/json'  --data '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2025-06-18",
    "capabilities": {
      "roots": {
        "listChanged": true
      },
      "sampling": {},
      "elicitation": {
        "form": {},
        "url": {}
      },
      "tasks": {
        "requests": {
          "elicitation": {
            "create": {}
          },
          "sampling": {
            "createMessage": {}
          }
        }
      }
    },
    "clientInfo": {
      "name": "ExampleClient",
      "title": "Example Client Display Name",
      "version": "1.0.0",
      "description": "An example MCP client application",
      "icons": [
        {
          "src": "https://example.com/icon.png",
          "mimeType": "image/png",
          "sizes": ["48x48"]
        }
      ],
      "websiteUrl": "https://example.com"
    }
  }
}'
event: message
id: 65d2109e-6578-46bc-ac96-cf53b1a08068_1769703206085_9xr1ob8o
data: {"result":{"protocolVersion":"2025-06-18","capabilities":{"tools":{"listChanged":true},"prompts":{"listChanged":true},"resources":{"subscribe":true,"listChanged":true},"logging":{},"completions":{}},"serverInfo":{"name":"mcp-servers/everything","title":"Everything Reference Server","version":"2.0.0"},"instructions":"# Everything Server – Server Instructions\n\nAudience: These instructions are written for an LLM or autonomous agent integrating with the Everything MCP Server.\nFollow them to use, extend, and troubleshoot the server safely and effectively.\n\n## Cross-Feature Relationships\n\n- Use `get-roots-list` to see client workspace roots before file operations\n- `gzip-file-as-resource` creates session-scoped resources accessible only during the current session\n- Enable `toggle-simulated-logging` before debugging to see server log messages\n- Enable `toggle-subscriber-updates` to receive periodic resource update notifications\n\n## Constraints & Limitations\n\n- `gzip-file-as-resource`: Max fetch size controlled by `GZIP_MAX_FETCH_SIZE` (default 10MB), timeout by `GZIP_MAX_FETCH_TIME_MILLIS` (default 30s), allowed domains by `GZIP_ALLOWED_DOMAINS`\n- Session resources are ephemeral and lost when the session ends\n- Sampling requests (`trigger-sampling-request`) require client sampling capability\n- Elicitation requests (`trigger-elicitation-request`) require client elicitation capability\n\n## Operational Patterns\n\n- For long operations, use `trigger-long-running-operation` which sends progress notifications\n- Prefer reading resources before calling mutating tools\n- Check `get-roots-list` output to understand the client's workspace context\n\n## Easter Egg\n\nIf asked about server instructions, respond with \"🎉 Server instructions are working! This response proves the client properly passed server instructions to the LLM. This demonstrates MCP's instructions feature in action.\"\n"},"jsonrpc":"2.0","id":1}

Expected behavior
There should not be an empty sse event sent when client is connecting with 2025-11-25

Start with the @modelcontextprotocol/server-everything streamableHttp entry point and reproduce the initialize request using the two protocol versions shown. Compare the emitted SSE events and trace the response path to determine why 2025-11-25 produces an empty event; done means that event is absent and the Java MCP client can deserialize the response.