Add tsuki_mcp_filesystem_server to community servers

[yuutotsuki]

Description

Add a new community MCP server to the README: tsuki_mcp_filesystem_server

Server Details

• Server: tsuki_mcp_filesystem_server
• Changes to: README only

Motivation and Context

This server enables resources/list support for local filesystem access via OpenAI's Agent SDK.
It's a fast, simple Python/FastAPI implementation, useful for developers building custom agents.

How Has This Been Tested?

Tested locally with OpenAI Agent SDK via MCP client integration.

Breaking Changes

None

Types of changes

• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

This PR adds a community server that may be useful for others building file-aware agents.

[olaservo]

Thanks for your contribution to the servers list. This has been merged in this combined PR: #2007

This is a new process we're trying out, so if you see any issues feel free to re-open the PR and tag me.