Feat/perplexity (#1719)

.changeset/rude-swans-fetch.md

examples/package.json

examples/perplexity.ts

packages/providers/perplexity/package.json

packages/providers/perplexity/src/index.ts

packages/providers/perplexity/src/llm.ts

packages/providers/perplexity/tsconfig.json

pnpm-lock.yaml

tsconfig.json