docs: add Hubspot server to community servers

[buryhuang]

Description

A new MCP server implementation that enables Claude to interact with HubSpot CRM data. The server provides direct access to contacts and companies through standardized MCP resources and tools.

Server Details

Server: hubspot
Changes to: README.md only (adding server reference)

Motivation and Context

This server enables AI assistants to directly interact with HubSpot CRM data, allowing for seamless contact and company management through natural language conversations. It fills a gap in the MCP ecosystem for CRM integrations.

How Has This Been Tested?

Tested with Claude Desktop client
Scenarios tested:

• Retrieving contacts and companies
• Creating new contacts with various properties
• Creating new companies with domain information
• Error handling for missing access tokens
• Error handling for invalid API requests

Breaking Changes

No breaking changes as this is a new server implementation.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• 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