Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

The PrintWriter stub is only used by tests that hit the prerender path;
pass-through tests don't read it and Mockito strict mode flags it as
UnnecessaryStubbing. Mark only that one line lenient.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Lets the backend correlate requests with a specific integration version
and uniquely identify each request for support triage.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Spawns the mock via ProcessBuilder, points the filter at it with a
real HttpClient, and asserts the recorded outgoing request shape
(URL, required headers, Int-Type, Int-Version semver, Request-Id
UUID format and per-request uniqueness, token omission).

CI installs Node alongside JDK and fetches mock-server.mjs from
prerender/integration-contract before running mvn test.

Jackson added as test-scoped dependency for JSON parsing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>