Add Synter Ads MCP Server

[jshorwitz]

Server Name: Synter Ads | URL: https://mcp.syntermedia.ai/mcp/ | GitHub: https://github.com/jshorwitz/synter-mcp-server | Description: Cross-platform ad campaign management for AI agents across Google, Meta, LinkedIn, Reddit, TikTok, and more. 140+ tools with read/write access.