Improve integration test harperLifecycle: rename setupHarper, add docs for killHarper/logDir/env vars

[Ethan-Arrowood]

Summary

• Renames setupHarper → startHarper throughout (clearer name; makes the restart pattern killHarper / startHarper read naturally)
• Collapses the old startHarper passthrough into the single startHarper implementation
• Documents previously undocumented exports: killHarper, HarperContext, logDir, and env vars HARPER_INTEGRATION_TEST_LOG_DIR, HARPER_INTEGRATION_TEST_INSTALL_PARENT_DIR, HARPER_INTEGRATION_TEST_INSTALL_SCRIPT
• Fixes stale .mts file extension references in README (actual files are .ts)
• Corrects SetupHarperOptions → StartHarperOptions and marks config/env as required to match the interface
• Adds process and logDir fields to the ContextWithHarper interface definition in the docs

Test plan

• Verify existing integration tests still import and run correctly with the renamed startHarper
• Check that crash-replay.test.ts restart pattern (killHarper → startHarper) works end-to-end

🤖 Generated with Claude Code

[DavidCockerill]

Nice!

These naming changes will also need to be updated in harper-pro

[cb1kenobi]

LGTM

[kriszyp]

This looks good, but like David said, would be nice to have a corresponding harper-pro PR since this will break the tests there, I believe. Should be an easy rename though.

[Ethan-Arrowood]

Okay before I merge I will work on harper-pro PR too.

[heskew]

nice update 👍

[Ethan-Arrowood]

Okay I created the harper-pro PR. I'm going to squash and merge this now and then get things updated on the harper-pro side