feat: add Perplexity Search API example (Python + TypeScript)

[jliounis]

Summary

Adds a Perplexity Search API recipe to the cookbook, following the same pattern as the existing Firecrawl and Exa examples (third-party search/data API + E2B sandbox for analysis).

Two parallel examples are included:

• examples/perplexity-search-js/ — TypeScript / Node, mirrors the mcp-groq-exa-js style.
• examples/perplexity-search-python/ — Poetry project, mirrors the hello-world-python / langchain-python style.

Both call POST https://api.perplexity.ai/search directly (no extra SDK), then write the JSON results into an E2B sandbox and run a small Python snippet that prints the top domains and result snippets.

Search options exposed

• query (required)
• max_results (configurable, not hardcoded — defaults to the API default of 10 unless set)
• search_domain_filter (allowlist or -domain.com denylist; not mixed)
• search_recency_filter (hour|day|week|month|year)

Auth

• Reads PERPLEXITY_API_KEY, falls back to PPLX_API_KEY.
• API key signup: https://www.perplexity.ai/account/api/keys

Wiring

• README: added a bullet under Example use cases linking both examples.
• tests/examples.test.ts: registered perplexity-search-js (npm) and perplexity-search-python (poetry).
• tests/utils.ts: added PERPLEXITY_API_KEY to the env passthrough used by the integration harness.

How to run

TypeScript:

cd examples/perplexity-search-js
cp .env.template .env  # set E2B_API_KEY and PERPLEXITY_API_KEY
npm install
npm start

Python:

cd examples/perplexity-search-python
cp .env.template .env
poetry install
poetry run start

Validation

• TypeScript example typechecks (npx tsc --noEmit).
• Python example parses and imports (no syntax errors).
• Both follow the existing cookbook examples' layout so they slot into the existing tests/examples.test.ts integration harness.

Docs

• Search quickstart: https://docs.perplexity.ai/docs/search/quickstart
• Search API reference: https://docs.perplexity.ai/api-reference/search-post
• Domain filter: https://docs.perplexity.ai/docs/search/filters/domain-filter
• Date / recency filter: https://docs.perplexity.ai/docs/search/filters/date-time-filters

[jliounis]

All checks are green and the PR has been clean since it opened. Could a maintainer take a look when you have a moment? Both the TS and Python examples follow the existing cookbook structure and exercise the Search API end-to-end via the E2B sandbox. Happy to address any feedback.