[qirh]

Summary

Perplexity would like to identify OwnPilot API traffic in request and billing telemetry. This adds X-Pplx-Integration: ownpilot to the existing Perplexity provider configuration.

OwnPilot already merges provider-specific headers into health checks, model discovery, synchronous completions, and streaming requests, so no request-client code changes are needed.

Verification

• The Perplexity provider config parses with X-Pplx-Integration: ownpilot.
• Existing provider-config and custom-header coverage passes, 180 tests.
• The changed JSON passes the repository's formatting check.

[qirh]

@ersinkoc could you approve the CI run for this fork and review when you get a moment? It is a one-header change to the Perplexity provider so Perplexity can recognise OwnPilot traffic, nothing else in the provider changes.