Fix filesystem MCP package in config docs

[w287346141]

Summary

• correct the configuration guide CLI example to use the official @modelcontextprotocol/server-filesystem package
• keep the CLI example consistent with the rest of the docs and MCP catalog

Validation

• git grep -n "@mcp/server-filesystem" -- . returned no matches
• npm.cmd test -- --run tests/docs-homepage-style.test.ts tests/carbon-productization.test.ts
• push hook ran npm.cmd run verify