Use Perplexity Web Search with Vercel AI Gateway

Introduces provider-agnostic web search functionality to Vercel AI Gateway using Perplexity. This is achieved by integrating `gateway.tools.perplexitySearch()` from `@ai-sdk/gateway` into the `tools` parameter of model calls. The post demonstrates use cases for models without native search, developer tooling, provider-agnostic chatbots, and operational agents. It also mentions provider-specific tools and pricing for the Perplexity search feature.