Add Pollinations.AI to Third-party APIs section

[voodoohop]

This PR adds Pollinations.AI to the Third-party APIs section.

Pollinations.AI provides free, no-signup APIs for text, image, and audio generation with no API keys required. It's particularly useful for:

• Educational settings where API keys are impractical
• Developers looking for quick integration of generative AI
• Projects needing OpenAI-compatible interfaces without the cost

The service offers:

• Text generation API (OpenAI-compatible)
• Image generation API
• Audio generation API
• React hooks for frontend integration
• MCP (Model Context Protocol) server for AI assistants

All APIs are accessible via HTTPS with CORS support.

Website: https://pollinations.ai Documentation: https://github.com/pollinations/pollinations/blob/master/APIDOCS.md